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H Hollema

Publications and source records attributed to H Hollema.

At least 55 records · Page 3Linked to original sources
PubMed2001

Computer-based diagnostic support systems in histopathology: what should they do?

In many fields in histopathology diagnosis making is notoriously difficult. We explored the diagnostic process in the area of CL and related disorders. The field of cutaneous lymphomas (CL) and borderline lesions is complex and representative for the type of diagnostic problems encountered. A review of diagnostic support systems in diagnostic pathology revealed that the usefulness of these systems has been disappointing. We contribute this to the fact that these systems target only part of the diagnostic process. A tentative model of diagnosis making in pathology is presented. This model assumes a two-step process, from observation to feature recognition and from features to diagnosis. In a retrospective study of existing skin biopsy pathology reports we assessed detail and scope of the histological descriptions. In a second, prospective study, a pathologist panel described a set of 16 skin biopsies using a standard set of descriptors. The retrospective study showed a large variability in the nature and details of described features, whereas the prospective study showed lack of consensus regarding both feature descriptions and diagnostic category. Both studies provide an indication that lack of consensus in feature recognition may be an important contributor to lack of consensus at the diagnostic level. Diagnostic expert systems target the step from feature to diagnosis. Evidently different input into such systems produces different output. We conclude that support of the feature recognition step can contribute to better diagnostic consensus because of more uniform interpretation of observations.

Biopsy↗
PubMed2000

Soft tissue leiomyosarcomas and malignant gastrointestinal stromal tumors: differences in clinical outcome and expression of multidrug resistance proteins.

PURPOSE: Several studies have reported clinical behavior and chemotherapy resistance in leiomyosarcomas, but these studies did not differentiate between soft tissue leiomyosarcomas (LMS) and malignant gastrointestinal stromal tumors (GIST). Multidrug resistance (MDR) has been associated with the expression of P-glycoprotein (P-gp), multidrug resistance protein (MRP(1)), and lung resistance protein (LRP). The aim of the present study was to compare LMS and GIST with respect to clinical outcome and MDR parameters. PATIENTS AND METHODS: Clinical outcome was evaluated in 29 patients with a primary deep-seated LMS and 26 patients with a primary malignant GIST. Paraffin-embedded material, available for 26 patients with LMS and 25 with GIST, was used for immunohistochemical detection of P-gp, MRP(1), LRP, and c-kit. RESULTS: Mean overall survival (OS) was 72 months for LMS patients and 31 months for GIST patients (P: <.05). Metastases occurred in 16 (59%) of 27 assessable LMS patients and in 10 (56%) of 18 assessable GIST patients. LMS predominantly metastasized to the lungs (14 of 16 patients), whereas GIST tended to spread to the liver (five of 10 patients) and the abdominal cavity (three of 10 patients; P: <.001). P-gp and MRP(1) expression was more pronounced in GIST than in LMS (P: <.05): the mean percentage of P-gp expressing cells was 13.4% in patients with LMS and 38.4% in patients with GIST, and the mean percentage MRP(1) expressing cells was 13.3% in patients with LMS and 35.4% in patients with GIST. LRP expression did not differ between LMS and GIST. c-kit was expressed in 5% of the LMS patients and in 68% of the GIST patients. CONCLUSION: LMS patients have a better survival than GIST patients, and the metastatic pattern is different. Expression of MDR proteins in LMS is less pronounced than in GIST.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Risk and prognosis of endometrial cancer after tamoxifen for breast cancer. Comprehensive Cancer Centres' ALERT Group. Assessment of Liver and Endometrial cancer Risk following Tamoxifen.

BACKGROUND: Tamoxifen increases the risk of endometrial cancer. However, few studies have produced reliable risk estimates by duration, dose, and recency of use, or addressed the prognosis of endometrial cancers in tamoxifen-treated women. METHODS: We did a nationwide case-control study on the risk and prognosis of endometrial cancer after tamoxifen use for breast cancer. Information on tamoxifen use and other risk factors for endometrial cancer was obtained from 309 women with endometrial cancer after breast cancer (cases), and 860 matched controls with breast cancer but without endometrial cancer. For 276 cases, we obtained tissue blocks of endometrial cancer to review the diagnosis, and used immunohistochemistry to examine hormone-receptor status and overexpression of p53. FINDINGS: Tamoxifen had been used by 108 (36.1%) of 299 cases and 245 (28.5%) controls (relative risk 1.5 [95% CI 1.1-2.0]). Risk of endometrial cancer increased with longer duration of tamoxifen use (p < 0.001), with relative risks of 2.0 (1.2-3.2) for 2-5 years and 6.9 (2.4-19.4) for at least 5 years compared with non-users. Endometrial cancers of stage III and IV occurred more frequently in long-term tamoxifen users (> or = 2 years) than in non-users (17.4% vs 5.4%, p=0.006). Long-term users were more likely than non-users to have had malignant mixed mesodermal tumours or sarcomas of the endometrium (15.4% vs 2.9%, p < or = 0.02), p53-positive tumours (31.4% vs 18.2%, p=0.05), and negative oestrogen-receptor concentrations (60.8% vs 26.2%, p < or = 0.001). 3-year endometrial-cancer-specific survival was significantly worse for long-term tamoxifen users than for non-users (76% for > or = 5 years, 85% for 2-5 years vs 94% for non-users, p=0.02). INTERPRETATION: Long-term tamoxifen users have a worse prognosis of endometrial cancers, which seems to be due to less favourable histology and higher stage. However, the benefit of tamoxifen on breast-cancer survival far outweighs the increased mortality from endometrial cancer. Nevertheless, we seriously question widespread use of tamoxifen as a preventive agent against breast cancer in healthy women.

Aged↗
PubMed2000

Inclusion of malignant fibrous histiocytoma in the tumour spectrum associated with hereditary non-polyposis colorectal cancer.

Sarcomas, including the malignant fibrous histiocytomas (MFHs), are not known to be part of the tumour spectrum of hereditary non-polyposis colorectal cancer (HNPCC) as epidemiologically established. Therefore, occurrence of MFH in an HNPCC family may very well be coincidental. HNPCC is associated with germline mutations in DNA mismatch repair genes, including the MSH2 gene. We analysed an MFH diagnosed in a 45-year-old male HNPCC patient carrying a germline MSH2 mutation for HNPCC-associated molecular characteristics, to investigate a possible relationship between the tumour and that mutation. DNA analysis revealed microsatellite instability and loss of one MSH2 copy, and immunohistochemistry showed absence of nuclear MSH2 protein staining. To investigate whether this is a common finding in MFH, microsatellite instability and nuclear MSH2 protein staining was tested for in 5 and 6 sporadic MFHs, respectively. None showed microsatellite instability and all stained positively for MSH2. Together, these findings show that in rare cases, MFH may be part of the HNPCC tumour spectrum.

Adenocarcinoma↗
PubMed2000

Serum CA 125, carcinoembryonic antigen, and CA 19-9 as tumor markers in borderline ovarian tumors.

OBJECTIVES: The goals of this study were to analyze preoperative serum levels of CA 125, carcinoembryonic antigen (CEA), and CA 19-9 in patients with borderline ovarian tumors and to investigate if routine assessment of these markers in follow-up may lead to earlier detection of recurrence. METHODS: For patient identification a database was used, in which data from all patients treated for gynecologic malignancies in the Department of Gynecologic Oncology, University Hospital Groningen, The Netherlands, are compiled. Between 1982 and 1997, 44 patients with borderline ovarian tumors were identified. Clinical data and serum CA-125 and CEA levels were retrieved from the database. CA 19-9 levels were determined in retrospect in available stored preoperative (24 patients) and follow-up (43 patients) serum samples. RESULTS: Preoperative CA 125 levels were elevated in 8 of 33 (24%), CEA levels in 3 of 32 (9%), and CA 19-9 levels in 11 of 24 (46%) cases. In patients with mucinous tumors preoperative CA 19-9 was more frequently elevated (8/14, 57%) than CA 125 (3/20, 15%) (P = 0.02) or CEA (2/18, 11%) (P = 0.02). Complete follow-up serum CA 125, CEA, and CA 19-9 levels were available for 43 of 44 patients. Median follow-up was 84 months (range, 22-204). During follow-up two patients (5%) had recurrent disease. In one patient CA 125 became elevated at the time of recurrence; in the other patient (in retrospect) the CA 19-9 level did not return to normal after surgery, but kept rising, preceding clinical symptoms of recurrence for 13 months. CONCLUSIONS: If one chooses to use serum markers in follow-up of mucinous borderline ovarian tumors CA 19-9 should be included. Measurement of serum tumor markers in the follow-up of patients with borderline ovarian tumors may lead to earlier detection of recurrence in only a very small proportion of patients, while the clinical value of earlier detection of recurrence remains to be established.

Adenocarcinoma, Mucinous↗
PubMed2000

The 16p11 breakpoint in myxoid liposarcomas might affect the expression of the LRP gene on 16p11.2 encoding the multidrug resistance associated major vault protein.

BACKGROUND: Chromosome breakage could influence the expression of genes. This has been noticed in specific cases of acute myeloid leukaemia, where the 16p13 breakpoint affects the expression of the multidrug resistance related protein (MRP). Myxoid liposarcomas (LPS) are characterized by the t(12; 16)(q13; p11), which leads to the formation of a FUS-CHOP fusion transcript. This study investigates the relationship between the cytogenetically detected breakpoint 16p11 in myxoid LPS, the presence of the FUS-CHOP fusion transcript in nonmyxoid LPS and the expression of the lung resistance major vault protein (LRP) gene on 16p11.2. MATERIALS AND METHODS: Of 16 cases with a diagnosis of a (possible) liposarcoma with an abnormal karyotype, fresh frozen tumour material was available for immunohistological detection of LRP. Cases without a cytogenetically detected t(12; 16)(q13; p11), were analyzed for the presence of a FUS-CHOP fusion transcript by RT-PCR. RESULTS: In all 9 myxoid LPS a t(12; 16)(q13; p11) was found and LRP expression was absent or low. In none of the remaining 7 cases was a FUS-CHOP fusion transcript found, and four tumours were LRP positive (P = 0. 02). LRP expression in myxoid LPS (mean: 1.3%) was lower (P = 0.07) than in the nonmyxoid tumours (mean: 35.7%). CONCLUSIONS: These observations indicate a relation between the t(12; 16)(q13; p11), leading to a FUS-CHOP fusion transcript in myxoid LPS, and the low or absent expression of the LRP-gene located on 16p11.2.

Chromosome Aberrations↗
PubMed2000

Telomerase in (pre)neoplastic cervical disease.

This study was performed to determine upregulation of the human telomerase RNA component (hTR) and mRNA of the catalytic subunit of telomerase (hTERT) in (pre)malignant cervical lesions, to analyze possible intralesional heterogeneity of hTR expression, and to relate hTR and hTERT mRNA levels to telomerase activity levels and human papillomavirus (HPV) typing. hTR expression was determined by in situ hybridization (ISH) on paraffin-embedded sections, obtained from patients with cervical intraepithelial neoplasia (CIN) I-III or cervical cancer and from normal controls. hTR and hTERT mRNA expression were determined by semiquantitative rt-PCR on frozen samples from the same lesions. Data on telomerase activity and HPV were obtained from a previous study. hTR expression as determined by ISH was observed in 0 of 8 normal cervices, 1 of 14 CIN I, 15 of 28 CIN II, 21 of 30 CIN III, and 16 of 18 cervical cancer specimens. In general, hybridization patterns for hTR expression were homogeneous throughout the lesion. Frequency of hTR expression was related to grade of CIN/cervical cancer (P<.001). hTR expression, as determined by rt-PCR, was detected in 8 of 8 normal cervices, 2 of 2 CIN I, 12 of 14 CIN II, 23 of 23 CIN III, and 16 of 17 cervical cancer specimens. hTERT mRNA was detected in 1 of 8 normal cervices, 1 of 2 CIN I, 5 of 14 CIN II, 14 of 23 CIN III, and 11 of 17 cervical cancer specimens. hTR as determined by rt-PCR was not related to grade of CIN/cervical cancer, whereas hTERT mRNA expression was related to grade of CIN/cervical cancer (P<.01). hTR expression, as determined by ISH and hTERT mRNA expression by rt-PCR, were related to telomerase activity levels (P<.001, P<.05, respectively) and presence of oncogenic types of HPV (both P<.05). Our data show frequent upregulation of hTR and hTERT mRNA expression in CIN lesions, which appear to occur earlier than induction of telomerase activity. The fact that semiquantitative hTERT mRNA as well as hTR levels are related to telomerase activity levels illustrates that in (pre)malignant cervical lesions upregulation of both telomerase components may be important for functional telomerase.

Catalytic Domain↗
PubMed2000

Adrenocortical adenocarcinoma in an MSH2 carrier: coincidence or causal relation?

A woman is described who developed an ovarian adenocarcinoma, 3 metachronous colorectal adenocarcinomas, and a primary adrenocortical adenocarcinoma. Genetic investigation of the mismatch repair genes MLH1 and MSH2 showed a germline mutation in MSH2. Colorectal and ovarian carcinoma belong to the tumor spectrum of hereditary nonpolyposis colorectal cancer (HNPCC). Adrenocortical adenocarcinoma, however, has never been described as 1 of the HNPCC-associated tumors. To investigate whether the adrenocortical adenocarcinoma in this patient was caused by the MSH2 germline mutation, determination of microsatellite instability (MSI) and immunohistochemical analysis were performed on 1 of the colorectal tumors and the adrenocortical adenocarcinoma. MSI and general loss of MSH2 protein expression could be seen in the colorectal tumor but not in the adrenocortical adenocarcinoma. Therefore, it is highly unlikely that the adrenocortical adenocarcinoma found in this patient was due to her genetic predisposition for HNPCC. HUM PATHOL 31:1522-1527.

Adenocarcinoma↗
PubMed2000

Sentinel lymph node procedure is highly accurate in squamous cell carcinoma of the vulva.

PURPOSE: To determine the diagnostic accuracy of the sentinel lymph node procedure in patients with squamous cell carcinoma of the vulva and to investigate whether step sectioning and immunohistochemistry of sentinel lymph nodes increase the sensitivity for detection of metastases. PATIENTS AND METHODS: Between July 1996 and July 1999, 59 patients with primary vulvar cancer were entered onto a two-center prospective study. All patients underwent sentinel lymph node procedure with the combined technique (preoperative lymphoscintigraphy with technetium-99m-labeled nanocolloid and intraoperative blue dye). Radical excision of the primary tumor with uni- or bilateral inguinofemoral lymphadenectomy was performed subsequently. Sentinel lymph nodes and lymphadenectomy specimens were sent for histopathologic examination separately. Sentinel lymph nodes, negative at the time of routine pathologic examination, were re-examined with step sectioning and immunohistochemistry. RESULTS: In 59 patients, 107 inguinofemoral lymphadenectomies were performed (11 unilateral and 48 bilateral). All sentinel lymph nodes, as observed on preoperative lymphoscintigram, were identified successfully intraoperatively. Routine histopathologic examination showed lymph node metastases in 27 groins, all of which were detected by the sentinel lymph node procedure. The negative predictive value for a negative sentinel lymph node was 100% (97.5% confidence interval [CI], 95% to 100%). Step sectioning and immunohistochemistry showed four additional metastases in 102 sentinel lymph nodes (4%; 95% CI, 1% to 9%) that were negative at the time of routine histopathologic examination. CONCLUSION: Sentinel lymph node procedure with the combined technique is highly accurate in predicting the inguinofemoral lymph node status in patients with early-stage vulvar cancer. Future trials should focus on the safe clinical implementation of the sentinel lymph node procedure in these patients. Step sectioning and immunohistochemistry slightly increase the sensitivity of detecting metastases in sentinel lymph nodes and should be included in these trials.

Adult↗
PubMed1999

Structural alterations of transforming growth factor-beta receptor genes in human cervical carcinoma.

The development and progression of invasive uterine cervical carcinomas appear to be associated with the progressive loss of sensitivity to transforming growth factor-beta (TGFbeta)-mediated cell cycle arrest. In order to identify possible molecular mechanisms responsible for TGFbeta resistance, we screened the 7 exons of the type II (TbetaR-II) TGFbeta receptor and the 9 exons of the type I (TbetaR-I) TGFbeta receptor genes for mutations in 16 paraffin-embedded primary invasive cervical carcinoma specimens. In one of these carcinomas, we found a novel G-->T transversion in exon 3 of TbetaR-II that introduces a premature stop codon (E142Stop) and presumably results in the synthesis of a truncated soluble exoreceptor. In one tumor, a silent A-->C transversion mutation that may affect mRNA splicing was present in exon 6 of TbetaR-I. In addition, 7 of 16 cases were heterozygous for a G-->A polymorphism in intron 7 of TbetaR-I. Finally, we identified a 9 base pair in-frame germline deletion in exon 1 of TbetaR-I resulting in loss of 3 of 9 sequential alanine residues at the N-terminus in 6 of 16 cases. Analysis of specimens from case-control studies indicated that carriers of this del(GGC)3 TbetaR-I variant allele may be at a increased risk for the development of cervical carcinoma (p=0.22). Furthermore, the response of cells expressing the variant receptor to TGFbeta was diminished. Our results support the notion that diverse alterations in the TGFbeta signaling pathway may play a role in the development of cervical cancer.

Adult↗
PubMed1999

Heat-shock-protein-27 (hsp27) expression in ovarian carcinoma: relation in response to chemotherapy and prognosis.

Heat-shock protein 27 (hsp27) is one of the small heat-shock proteins. Its expression in ovarian- and breast-cancer cell lines has been associated with resistance to cisplatin and doxorubicin. In addition, hsp27 expression appears to facilitate cellular growth, differentiation and motility. In several human carcinomas, hsp27 expression might also be related to worse prognosis. The aim of this study was to evaluate the prognostic value of hsp27 expression in patients with ovarian carcinoma in relation to their response to chemotherapy and overall survival. Hsp27 expression was assessed by immunohistochemistry in 77 patients with ovarian carcinoma stage IC-IV. All patients received cisplatin- and doxorubicin-based chemotherapy and had long-term follow-up. In 30 patients, paired tumour samples were available, obtained before and after chemotherapy. Hsp27 immunostaining was positive in 86% of patients before and in 72% of patients after chemotherapy. Hsp27 expression was not related to any clinicopathologic factor, including previously determined p53 expression. Univariate analysis showed that, in stage-III and -IV patients, younger age, no residual tumour after first laparotomy, < or = 1 litre ascites, response to first-line chemotherapy and absence of hsp27 expression were associated with longer median progression-free survival. However, in multivariate analysis, only age, ascites and response to chemotherapy retained independent prognostic value.

Adult↗
PubMed1999

Discrepancy between ultrasonography and hysteroscopy and histology of endometrium in postmenopausal breast cancer patients using tamoxifen.

BACKGROUND: The increased risk of endometrial carcinoma following the use of tamoxifen has stimulated studies on endometrial diagnostic screening methods. In tamoxifen users the endometrial thickening observed with transvaginal ultrasonography (TVU) frequently cannot be confirmed by hysteroscopy or histology. OBJECTIVE: The aim was to investigate the relationship between TVU and hysteroscopic and histologic endometrial findings in postmenopausal patients using tamoxifen. METHODS: Fifty-three asymptomatic postmenopausal tamoxifen-using breast cancer patients underwent a gynecological examination combined with TVU. Patients with an endometrial thickness of >5 mm were offered hysteroscopy and endometrial biopsy. FINDINGS: Thirty-one patients (58%) had an endometrial thickness of >5 mm with enhanced, inhomogeneous echogenicity. Hysteroscopy was performed in 22 patients and 3 underwent hysterectomy. Seven of 22 patients had endometrial polyps, histologically characterized by cystically dilated glands lined with atrophic epithelium and periglandular stromal condensation. Histology of the three hysterectomy specimens showed a similar picture of atrophic luminal epithelium, covering dilated glands lined with atrophic epithelium and surrounded by dense stroma, which resembled the histology of the endometrial polyps. In all three specimens the histologically measured endometrial thickness corresponded with that on TVU. INTERPRETATION: Tamoxifen can induce specific endometrial changes consisting of cystically dilated glands with periglandular stromal condensation while the overlying epithelium remains atrophic. The changes occur either in the endometrium itself or as a protrusion of the endometrium, i.e., as endometrial polyps. These findings explain the discrepancy between ultrasound, hysteroscopy, and histology. Due to the high number of false-positive findings, TVU is not an effective screening instrument in these patients.

Adult↗
PubMed1999

The importance of family history in young patients with endometrial cancer.

Endometrial cancer occurs primarily in postmenopausal women older than 60 years of age. Especially in young patients with endometrial cancer, a positive family history with respect to cancer and/or development of synchronous or metachronous tumors can be indicative of hereditary factors. One genetic disorder, playing an important role in the development of endometrial cancer in young women, is hereditary non-polyposis colorectal cancer (HNPCC). The mean age to develop endometrial cancer because of a mutation in one of the HNPCC-genes is below 50 years. Mutation carriers have a life-time risk of about 50% for endometrial cancer. Especially young patients with endometrial cancer should always be asked for the family history and after primary treatment the family history should regularly be updated during follow-up.

Colorectal Neoplasms, Hereditary Nonpolyposis↗
PubMed1999

DNA topoisomerase IIalpha and -beta expression in human ovarian cancer.

To study DNA topoisomerase IIalpha (Topo-IIalpha) and -beta expression and regulation in human ovarian cancer, 15 ovarian tumour samples were investigated. To compare different levels of expression, the samples were screened for topo IIalpha and -beta mRNA with Northern blotting and a quantitative reverse transcriptase polymerase chain reaction (RT-PCR) assay for Topo-IIalpha mRNA. Additionally, protein levels were determined with Western blotting and topoisomerase II activity levels with the decatenation assay. The results obtained were compared with each other and with the tumour volume index of the samples. In tumours with a tumour volume index > or = 50%, the mRNA levels (as determined by Northern blotting) and protein levels for each isozyme were in accordance. Additionally, correlations were found between Topo-IIalpha RT-PCR data and Topo-IIalpha Northern blot results, and between Topo-IIalpha RT-PCR data and Topo-IIalpha protein levels. Interestingly, Topo-IIbeta protein levels correlated better with Topo-II activity than Topo-IIalpha protein levels. In eight ovarian cystadenoma samples, no Topo-IIalpha protein could be found. In only three out of eight of these cystadenomas, Topo-IIbeta protein could be detected. These findings suggest that Topo-IIalpha and Topo-IIbeta protein levels are up-regulated in ovarian cancer and may indicate that Topo-IIbeta is an interesting target for chemotherapy in ovarian tumours.

Adenocarcinoma↗
PubMed1999

Ovarian cysts in women receiving tamoxifen for breast cancer.

Tamoxifen is a nonsteroidal anti-oestrogen with gynaecological side-effects. Only recently, ovarian cyst formation during tamoxifen treatment has been reported. The present study aimed to evaluate patient-related parameters that determine ovarian cyst formation in women using tamoxifen for breast cancer. A cross-sectional study was performed in 142 breast cancer patients using tamoxifen. Forty-five patients were also examined prior to tamoxifen treatment. Gynaecological assessment, transvaginal ultrasonography (TVU) and serum oestradiol (E2) and follicle stimulating hormone (FSH) analysis were performed. Follow-up assessments were performed twice a year. Uni- or bilateral ovarian cysts were detected by TVU in 24 tamoxifen-using patients and in one patient before tamoxifen treatment. Multiple regression analysis showed that cyst development is related (multiple R = 0.73) to high E2 (P < 0.001), younger age (P < 0.001) and absence of high-dose chemotherapy (P = 0.007). Patients with ovarian cysts had higher serum E2 levels compared to patients without cysts (1.95 vs 0.05 nmol l(-1); P < 0.001). All patients after high-dose chemotherapy or older than 50 years had E2 < 0.10 nmol l(-1) and/or amenorrhoea > 1 year and did not develop ovarian cysts. Patients still having a menstrual cycle during tamoxifen had a high chance (81%) of developing ovarian cysts. Breast cancer patients receiving tamoxifen only develop ovarian cysts if their ovaries are able to respond to FSH stimulation as shown by E2 production.

Adult↗
PubMed1999

In squamous cell carcinoma of the vulva, overexpression of p53 is a late event and neither p53 nor mdm2 expression is a useful marker to predict lymph node metastases.

To offer more tailored treatment to individual patients with squamous cell carcinoma of the vulva, more accurate prediction of lymph node metastases is required. As p53 and mdm2 are genes known to be involved in the development of other tumours, we studied expression of p53 and mdm2 in carcinogenesis of squamous cell carcinoma of the vulva and their clinical relevance. Archival material of 141 T1 and T2 vulvar tumours were used. Of the 141 primary tumours, the corresponding 39 lymph node metastases (LNM) were studied, and in 90 cases the pre-existent epithelia adjacent to the tumour (EAT) and in 14 cases vulvar intraepithelial neoplasia adjacent to the tumour (VIN) was also investigated. Detection of p53 and mdm2 protein was immunohistochemically performed. Scoring categories were: negative (1); weakly positive (2); moderately to markedly positive (3); and markedly positive (4). Overexpression of p53 was seen in 56% of the LNM, 39% of the primary tumours, 21% of the VIN lesions and 0% in the group of EAT. No relation was found between overexpression of p53 in the primary tumour and LNM. Expression of mdm2 was seen in 14% of the primary tumours, of which four cases were marked positive. In the group of LNM no mdm2-positive staining was observed. In the group of EAT, 25% was mdm2-positive, of which six cases were marked positive. In the group of VIN, 36% showed moderate (score 3) mdm2 expression. No relation was found between expression of mdm2 and LNM. In squamous cell carcinoma, overexpression of p53 is a late event in carcinogenesis. Marked expression of mdm2 is rarely seen in vulvar carcinomas, indicating that aberrant p53 cannot induce mdm2 expression. LNM cannot be predicted by detection of these proteins.

Adult↗
PubMed1999

Association of hereditary nonpolyposis colorectal cancer-related tumors displaying low microsatellite instability with MSH6 germline mutations.

Hereditary nonpolyposis colorectal cancer (HNPCC) (Amsterdam criteria) is often caused by mutations in mismatch repair (MMR) genes, and tumors of patients with HNPCC show microsatellite instability (MSI-high phenotype). Germline mutations of MMR genes have rarely been found in families that have HNPCC or suspected HNPCC and that do not show microsatellite instability (MSI-low phenotype). Therefore, an MSI-high phenotype is often used as an inclusion criterion for mutation testing of MMR genes. Correction of base-base mismatches is the major function of MSH6. Since mismatches present with an MSI-low phenotype, we assumed that the phenotype in patients with HNPCC-related tumors might be associated with MSH6 germline mutations. We divided 36 patients with suspected HNPCC into an MSI-low group (n=18) and an MSI-high group (n=18), on the basis of the results of MSI testing. Additionally, three unrelated patients from Amsterdam families with MSI-low tumors were investigated. All patients were screened for MSH2, MLH1, and MSH6 mutations. Four presumably causative MSH6 mutations were detected in the patients (22%) who had suspected HNPCC and MSI-low tumors. Furthermore, we detected one frameshift mutation in one of the three patients with HNPCC and MSI-low tumors. In the MSI-high group, one MSH6 missense mutation was found, but the same patient also had an MLH1 mutation, which may explain the MSI-high phenotype. These results suggest that MSH6 may be involved in a substantial proportion of patients with HNPCC or suspected HNPCC and MSI-low tumors. Our data emphasize that an MSI-low phenotype cannot be considered an exclusion criterion for mutation testing of MMR genes in general.

Adaptor Proteins, Signal Transducing↗