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J F Moley

Publications and source records attributed to J F Moley.

At least 37 records · Page 2Linked to original sources
PubMed1999

Patterns of nodal metastases in palpable medullary thyroid carcinoma: recommendations for extent of node dissection.

OBJECTIVE: To establish the frequency, pattern and location of cervical lymph node metastases from palpable medullary thyroid carcinoma (MTC). Recommendations are made regarding the extent of surgery for this tumor. SUMMARY BACKGROUND DATA: Medullary thyroid carcinoma is a tumor of neuroendocrine origin that does not concentrate iodine. Surgical extirpation of the thyroid tumor and cervical node metastases is the only potentially curative therapeutic option. Patterns of node metastases in the neck and guidelines for the extent of dissection for palpable MTC are not well established. METHODS: Seventy-three patients underwent thyroidectomy for palpable MTC with immediate or delayed central and bilateral functional neck dissections. The number and location of lymph node metastases in the central (levels VI and VII) and bilateral (levels II to V) nodal groups were noted and were correlated with the size and location of the primary thyroid tumor. Intraoperative assessment of nodal status by palpation and inspection by the surgeon was correlated with results of histologic examination. RESULTS: Patients with unilateral intrathyroid tumors had lymph node metastases in 81% of central node dissections, 81% of ipsilateral functional (levels II to V) dissections, and 44% of contralateral functional (levels II to V) dissections. In patients with bilateral intrathyroid tumors, nodal metastases were present in 78% of central node dissections, 71% of functional (levels II to V) node dissections ipsilateral to the largest intrathyroid tumor, and 49% of functional (levels II to V) node dissections contralateral to the largest thyroid tumor. The sensitivity of the surgeon's intraoperative assessment for nodal metastases was 64%, and the specificity was 71%. CONCLUSION: In this series, >75% of patients with palpable MTC had associated nodal metastases, which often were not apparent to the surgeon. Routine central and bilateral functional neck dissections should be considered in all patients with palpable MTC.

Adult↗
PubMed1999

Preservation of the recurrent laryngeal nerves in thyroid and parathyroid reoperations.

BACKGROUND: The recurrent laryngeal nerve (RLN) is vulnerable to injury in thyroid and parathyroid reoperations because of the presence of scar tissue and displacement of the nerve from its normal position. METHODS: Since 1993, we have performed 132 reoperations for recurrence of thyroid or parathyroid carcinoma (102 cases), persistent hyperparathyroidism (21 cases), and recurrent goiter (9 cases). One or both RLNs were identified in all cases (208 nerves). Exposure of the nerve was accomplished by a lateral approach (159 nerves), a low anterior approach (41 nerves), or the identification of the nerve between the larynx and the upper pole of the thyroid, in parathyroid reoperations (8 nerves). Dissection was then done while the nerve was kept in view at all times. RESULTS: Preoperatively, unilateral vocal cord paralysis was noted in 6 patients. Resection of a functioning RLN encased with a tumor was intentionally carried out in 5 patients. The RLNs were identified and preserved in all other cases. Among these 121 patients, transient hoarseness lasting up to a month occurred in 12 patients. CONCLUSIONS: Careful identification and exposure of the RLN through a previously undissected area can be done safely in thyroid and parathyroid reoperations and resulted in no permanent recurrent nerve injuries in our experience.

Follow-Up Studies↗
PubMed1998

Four new mutations in the DNA mismatch repair gene MLH1 in colorectal cancers with microsatellite instability. Mutations in brief no. 157. Online.

Hereditary nonpolyposis colorectal cancer (HNPCC) is frequently associated with inherited mutation in one of four DNA mismatch repair genes. Somatic mutations in the same genes are also found in a subset of sporadic colorectal cancers. A defect in DNA mismatch repair results in a RER (replication error) tumor phenotype. We screened 110 archival and 11 prospectively acquired colorectal cancers for the RER phenotype. A total of 22 cancers were RER-positive. RER-positive tumors were investigated for mutations in the DNA mismatch repair gene MLH1 using single-strand-conformation-polymorphism (SSCP) analysis. We identified four previously undescribed mutations in four different samples. Three mutations were exonic: a point mutation at codon 69 (AGG-->AAG(arg-->lys]); a single base pair deletion at codon 42/43 (GCAAAATCC-->GCAAATCC) leading to a new stop codon downstream; and a point mutation at codon 757 (TAA-->TAT [termination-->tyr] which extend the MLH1 peptide by 36 ammino acids. The fourth mutation was a 1 base pair insertion six base pairs 5' to the start of exon 14 (tttgtttt-->tttggtttt). The mutations were not seen in the patients' constitutional DNA. The somatic MLHI mutations identified appear to be causally associated with the RER phenotype.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Surgical management of patients with persistent or recurrent medullary thyroid cancer.

Residual or recurrent medullary thyroid carcinoma (MTC), manifested by elevated calcitonin levels, occurs commonly following primary treatment of MTC. Re-operation in appropriately selected patients is the only treatment modality which consistently and reliably reduces stimulated calcitonin levels, and results in excellent local disease control. We report improved results of surgical management of recurrent MTC in two consecutive series of patients. In our most recent series (1992-96), 38% of patients (17 out of 45) had normal postoperative stimulated calcitonin levels, compared to 28% (nine of 32) in our first series (1990-92). In the most recent series, only 13% (six of 45) of patients had no decrease in calcitonin levels following re-operation, compared to 31% (10 of 32) in our first series (P = 0.07, Fisher's exact test). This improvement has mainly occurred through better preoperative selection of patients, and the institution of routine laparoscopic liver examination preoperatively, which identified metastases in 10 patients, nine of whom had normal CT or MRI imaging.

Adolescent↗
PubMed1998

Confirmation that chromosome 18q allelic loss in colon cancer is a prognostic indicator.

PURPOSE: Recent studies suggest that allelic loss of sequences from the long arm of chromosome 18 may be a useful prognostic indicator in colorectal cancer. The aim of the present study was to confirm whether 18q loss of heterozygosity (LOH) is of prognostic value in patients with colon cancer. METHODS: Genomic DNA was prepared from archival tumor and corresponding normal tissue specimens from 151 patients who had undergone potentially curative surgery for adenocarcinoma of the colon. Polymerase chain reaction (PCR) was used to assess allelic loss of five chromosome 18q microsatellite markers in the tumors. The relationship between allelic loss and disease-free and disease-specific survival was investigated. RESULTS: LOH was detected in 67 of 126 tumors. Chromosome 18q allelic loss was a negative prognostic indicator of both disease-free (relative risk [RR], 1.65; P = .01) and disease-specific survival (RR, 2.0; P = .003). 18q loss was also associated with significantly reduced disease-free and disease-specific survival in patients with stage II (P = .05 and P = .0156) and III (P = .038 and P = .032) disease. CONCLUSION: Chromosome 18q allelic loss is a prognostic marker in colorectal cancers. Chromosome 18 LOH studies may be useful in identifying patients with stage II disease who are at high risk for recurrence, and as such might benefit from adjuvant chemotherapy.

Adenocarcinoma↗
PubMed1998

Medullary thyroid carcinoma: genetic advances, treatment recommendations, and the approach to the patient with persistent hypercalcitoninemia.

Medullary thyroid cancer is a tumor of the thyroid C cells that occurs in sporadic and hereditary clinical settings. Genetic testing of at-risk individuals is available and has been applied to patient management. Plasma calcitonin levels are a sensitive marker for the presence of disease. Surgery offers the best hope for cure and also is an effective modality for managing metastatic and recurrent disease.

Biomarkers, Tumor↗
PubMed1997

Differential display in primary and metastatic medullary thyroid carcinoma.

Despite recent advances in the understanding of the role of the RET proto-oncogene in the development of familial and approximately 30% of sporadic medullary thyroid carcinomas (MTC), little is known about other genetic events that modify the course and outcome of the disease. We compared the expression of genes in intrathyroidal MTCs to autologous local lymph node metastases by means of mRNA differential display (DDRT-PCR). This is the first report of differential display using surgical specimens of a primary cancer and its metastases. Total RNA was extracted from tumor tissue of two patients with MTC associated with multiple endocrine neoplasia (MEN 2B) and sporadic MTC, respectively. Following reverse transcription (RT), the products were PCR-amplified and separated on a denaturating polyacrylamide gel. RT-PCR products demonstrating differential expression were reamplified and used as probes for Northern blot analysis. Six fragments for which differential expression was confirmed were cloned and sequenced. Resultant sequences were tested for homology to sequences in public data bases, and two novel MTC-derived fragments (MDF-1, MDF-2) were identified. Sensitivity of the method was confirmed by identification of a sequence encoding the calcitonin precursor flanking peptide which is expressed almost exclusively in MTC and normal thyroid C cells. Overexpression of the ribosomal genes S3a and P0 was found in the metastases. Recent reports suggest that components of the translational apparatus act as regulatory mediators of growth, proliferation, and neoplastic change. The altered expression of ribosomal proteins and gene products encoded by MDF-1 or MDF-2 may play an important role in the progression and metastatic spread of MTC.

Blotting, Northern↗
PubMed1997

Prognostic value of chromosome 1p allelic loss in colon cancer.

BACKGROUND & AIMS: Current evidence suggests that there may be a tumor-suppressor gene on chromosome 1p associated with colorectal cancer. The aim of the present study was to determine whether allelic loss on chromosome 1p is of prognostic value in colorectal cancer. METHODS: Polymerase chain reaction was used to assess allelic loss of five chromosome 1p microsatellite markers in tumor specimens. Genomic DNA was prepared from archival tumor and corresponding normal tissue specimens from 116 patients who had undergone curative treatment for adenocarcinoma of the colon. Allelic loss was correlated with disease-free interval and survival. RESULTS: Deletion of 1p sequence was detected in 22 of 82 tumors. Deletions of the microsatellite markers D1S228 (1p36) and HY-TM1 (1p32) were significantly associated with poor survival (P < 0.05): relative risk, 4.1; 95% confidence interval, 1.25-9.23 for D1S228; and relative risk, 6.6; 95% confidence interval, 1.4-19 for HY-TM1. Loss of heterozygosity at D1S228 was also associated with shorter disease-free interval: relative risk, 4.5; 95% confidence interval, 1.3-11. CONCLUSIONS: Allelic loss in the 1p36 and 1p32 regions of chromosome 1 appears to be an independent predictor of poor prognosis in patients with adenocarcinoma of the colon.

Adult↗
PubMed1997

Heterotopic autotransplantation of parathyroid tissue in children undergoing total thyroidectomy.

AIM: The purpose of this study was to examine the efficacy of parathyroid autotransplantation in children undergoing total thyroidectomy. METHODS: We have prospectively evaluated 32 cases of total thyroidectomy in children. The ages ranged from 1 year to 15.7 years, and the mean was 8.9 years. In 31 cases, the indication for surgery was a diagnosis of MEN2A or 2B based on direct DNA testing. One child had suspected sporadic medullary thyroid carcinoma. All of the patients underwent heterotopic autotransplantation of parathyroid gland tissue. In 26 cases, the parathyroid tissue was placed in the nondominant forearm, while in 6 children it was autotransplanted into the sternocleidomastoid muscle. RESULTS: In 31 of 32 children (97%), the serum calcium level transiently decreased in the immediate postoperative period. All of the patients were placed on oral calcium carbonate and vitamin D supplementation, and the serum calcium levels became normal within several days. The supplemental medications were then weaned as tolerated. Within 3 months of their procedure, 30 patients (94%) had adequate parathyroid tissue engraftment, and the calcium and vitamin D medications were discontinued. One child required 9 months of calcium and vitamin D medications before she could be weaned from the medications. One child has been treated more recently, and is currently being weaned from supplemental calcium and vitamin D. Serum PTH levels in 22 patients who had placement of the tissue into their forearms were measured, and in each there was increased PTH in the grafted arm compared with the nongrafted arm. In five children who had parathyroid tissue grafted into the sternocleidomastoid muscle, the peripheral serum PTH levels were in the normal range. CONCLUSION: The heterotopic autotransplantation of resected parathyroid tissue is safe and effective in preventing permanent hypoparathyroidism.

Adolescent↗
PubMed1997

"Cold" single-strand conformational variants for mutation analysis of the RET protooncogene.

BACKGROUND: RET protooncogene mutation analysis is a routinely performed predictive DNA test in kindreds affected by multiple endocrine neoplasia (MEN) types 2A and 2B and familial medullary thyroid carcinoma (FMTC), and is a valuable diagnostic tool in newly diagnosed cases of medullary thyroid carcinoma (MTC). METHODS: We tested the suitability of the recently introduced "cold" single-strand conformational variant (SSCV) technique, which promises rapid, simple, nonradioactive detection of sequence variants in the identification of germline and somatic RET mutations. A total of 11 different mutations in exon 10 (codons 609, 611, 618, and 620) and 6 mutations in exon 11 (codon 634) were studied. RESULTS: Conditions were optimized so that conformational variants were demonstrated for all mutations examined in a single setting for exons 10 and 11. A novel six base pair (bp) inframe deletion between cysteines 630 and 634 was detected in a sporadic MTC. This adds to the evidence that not only cysteine deletions and substitutions but also changes in the spacing between cysteine residues have a pathogenic effect. CONCLUSIONS: Our results indicate that the cold SSCV method offers the advantages of simplicity, time savings, and nonradioactive detection for screening for RET sequence variants in hereditary and sporadic MTCs.

Amino Acid Sequence↗
PubMed1997

Evaluation of fluorodeoxyglucose-positron emission tomographic scanning and its association with glucose transporter expression in medullary thyroid carcinoma and pheochromocytoma: a clinical and molecular study.

BACKGROUND: Imaging of metastatic sites of medullary thyroid carcinoma (MTC) is successful in less than 60% of cases of residual or recurrent disease. Positron emission tomography (PET) with [18F]fluoro-2-deoxy-D-glucose (FDG) takes advantage of the fact that malignant tumors are capable of increased uptake and use of glucose, which is mediated by the members of the glucose transporter family of proteins (GLUT 1 through GLUT 5). METHODS: FDG-PET images of 10 patients with recurrent or persistent MTC after primary operation were compared with images by computed tomography or magnetic resonance imaging. Identified metastatic lesions were assessed by intraoperative findings and pathology reports. Expression of GLUT 1 through GLUT 5 was examined by Western blot analysis of tumor tissue from eight of the patients evaluated and an additional panel of 10 MTCs and seven pheochromocytomas. RESULTS: FDG-PET identified 31 foci of FDG accumulation in 10 patients, and 16 of these metastatic sites were resected and confirmed by histologic analysis. Only 11 foci were demonstrated by computed tomographic or magnetic resonance imaging. None of the glucose transporters examined displayed significant expression. Two pheochromocytomas were successfully imaged by FDG-PET. CONCLUSIONS: FDG-PET imaging can be useful in the localization of cervicomediastinal MTC metastases and pheochromocytoma. The increased glucose uptake in these tumors, as evidenced by FDG-PET, does not appear to be attributable to the expression of the glucose transporter proteins GLUT 1 through GLUT 5.

Adolescent↗
PubMed1997

Improved results of cervical reoperation for medullary thyroid carcinoma.

OBJECTIVE: The purpose of the study is to determine whether reoperation for medullary thyroid carcinoma (MTC), performed with low morbidity in carefully selected patients, consistently results in improvement as determined by lowering of stimulated calcitonin levels. BACKGROUND: Persistent or recurrent elevation of stimulated plasma calcitonin levels occurs in > 50% of patients after primary operation for MTC. Success of reoperation with clearance of metastatic cervical nodal disease has been hampered by failure to identify patients with distant metastases and by inadequate removal of involved nodal groups. METHODS: Since 1992, the authors have evaluated 115 patients with recurrent or residual MTC. Fifty-three patients have not undergone operation because of extent of disease, previous extensive treatment, medical condition, or patient choice. Sixty-two patients underwent surgery. Ten patients had laparoscopic or open examination of the liver, the results of which showed liver metastases. Seven patients had palliative debulking of cervical tumor. In 45 patients without evidence of distant metastases, cervical operation was carried out with curative intent. Removal of central, upper mediastinal, and lateral nodes (levels II, III, IV, VI, and VII) was done. RESULTS: Seven of eight patients who had palliative resections are alive without symptoms. In patients who underwent curative resections, postoperative stimulated calcitonin levels were in the normal range in 17 patients (38%) and were not significantly lowered in 6 patients (13%). There were no deaths, and no transfusions were used. CONCLUSIONS: These results are a significant improvement over the authors' previous series and reflect better preoperative identification of patients with disease confined to the neck and improved operative strategy based on knowledge of the pattern of nodal spread of MTC.

Adolescent↗
PubMed1997

The molecular genetics of multiple endocrine neoplasia type 2A and related syndromes.

Identification of RET gene mutations in patients at-risk for the development of the hereditary forms of medullary thyroid carcinoma has simplified management and expanded the scope of indications for surgical intervention. Patients who carry this mutation can be offered thyroidectomy at a very young age, hopefully at a point when the cancer has not yet developed or spread. Those who are found not to have inherited the mutation are spared further genetic and biochemical screening. This achievement marks a new paradigm in surgery--the recommendation that an operation be performed based on the result of a genetic test. Experience with management of patients with multiple endocrine neoplasia types 2A and 2B and with familial, non-multiple endocrine neoplasia medullary thyroid carcinoma will provide information that will aid in the future management of patients with other hereditary cancers.

Carcinoma, Medullary↗
PubMed1997

Absence of TP53 alterations in pheochromocytomas and medullary thyroid carcinomas.

The role of the TP53 gene in the development of inherited and sporadic pheochromocytomas and medullary thyroid carcinomas (MTC) has not been clarified because of conflicting reports and limitations in the assays used to detect mutations. To determine the frequency of TP53 alterations in these tumors, 22 pheochromocytomas and 29 MTCs were screened for loss of heterozygosity (LOH) on 17p with four markers. Single-strand-conformation-variant (SSCV) analysis of exons 4-9 of the TP53 gene was performed in 20 of the pheochromocytomas and in 22 of the MTCs. The expression of p53 was determined by immunohistochemistry in 19 pheochromocytomas and in 17 MTCs using two antibodies (D01 and D07) on frozen and paraffin-embedded tissues. Four of the 22 pheochromocytomas and none of the MTCs showed LOH on 17p. No mutations were detected in any of the tumors screened by SSCV analysis. Immunohistochemical staining of frozen and paraffin-embedded tumor sections did not show p53 overexpression in any of the tumors examined. Our findings indicate that mutations in the TP53 gene are an uncommon event in the tumorigenesis of pheochromocytomas and medullary thyroid carcinomas.

Adrenal Gland Neoplasms↗
PubMed1996

Medullary thyroid carcinoma in children with multiple endocrine neoplasia types 2A and 2B.

Recently it has become possible to identify persons who have multiple endocrine neoplasia (MEN) syndrome types 2A and 2B based on the presence of missense mutations in the RET protooncogene. Kindred members who have inherited these syndromes can be identified before clinical or biochemical evidence of medullary thyroid carcinoma (MTC) develops, the malignancy that occurs in all affected patients. It is not known whether prophylactic removal of the thyroid gland early in childhood, based on a positive genetic test result, has a better clinical outcome than that associated with thyroidectomy after MTC is diagnosed clinically or biochemically. The authors' goal was to determine the long-term outcome for patients with MEN 2A and 2B who had thyroidectomy for MTC during childhood. These results were compared with those of patients who had prophylactic removal of the thyroid gland after the genetic diagnosis of MEN 2A was established. The hospital records of 49 children with MEN 2A or 2B were reviewed. Each patient had thyroidectomy for MTC before 16 years of age. The mean age at the time of operation was 10 years, and the mean follow-up period for those who had surgery before the availability of direct DNA genetic testing was 9.8 years. The indications for surgery included an elevated basal or stimulated plasma calcitonin level, a positive genetic test result, a thyroid mass, family history of MTC, or a phenotype diagnostic of MEN 2B. All children for whom the diagnosis of MEN 2A was established by direct genetic testing had thyroidectomy within the last 2 years. Of the 11 patients with MEN 2B who underwent thyroidectomy during childhood, 10 had MTC, and only 3 (27%) remain free of disease after the mean follow-up period of 11 years. One patient died, and seven are alive with persistent MTC. Among the 24 patients with MEN 2A who had their thyroid glands removed because of a family history of MTC or because of biochemical evidence of the disease, 5 (21%) have persistent or recurrent MTC after the mean follow-up period of 9.3 years. In four of these, the MTC was confined to the thyroid gland at the time of thyroidectomy. Of the 14 children who had thyroidectomy based on direct DNA testing, MTC was present in 11. Only four had elevated levels of stimulated plasma calcitonin before surgery. None had lymph node metastasis or surgical complications. The authors conclude that a significant number of patients with MEN 2A or 2B who undergo thyroidectomy in childhood for MTC have persistent or recurrent disease long-term. The genetic diagnosis of patients with these syndromes may allow for prophylactic surgery before the development of biochemical or clinical evidence of MTC. This approach is safe, but longer clinical follow-up will be necessary to confirm that MTC has been cured.

Adolescent↗
PubMed1996

Laparoscopic adrenalectomy compared to open adrenalectomy for benign adrenal neoplasms.

BACKGROUND: Laparoscopic adrenalectomy has recently been used for removing a variety of adrenal neoplasms. The purpose of the present study was to compare results and outcomes in patients who underwent either laparoscopic or open adrenalectomy at our institution from 1988 to the present. STUDY DESIGN: The records of 66 consecutive patients with benign adrenal neoplasms who underwent adrenalectomy from 1988 through 1995 were retrospectively reviewed. Patients were divided into three groups based on the operative approach: group I (n = 25), open anterior transabdominal approach; group II (n = 17), open posterior retroperitoneal approach; and group III (n = 24), laparoscopic transabdominal flank approach. Various parameters were compared and statistical analyses were performed. RESULTS: The three groups were similar in age, gender, American Society of Anesthesiologists class, and distribution of unilateral compared with bilateral adrenalectomy. Mean tumor size was slightly larger in group I (3.4 +/- 1.4 cm) than in group II (2.4 +/- 1.4 cm) or group III (2.7 +/- 1.4 cm) (p = NS). Mean operative times for unilateral adrenalectomy were 142 +/- 38 minutes in group I, 136 +/- 34 minutes in group II, and 183 +/- 35 minutes in group III (p < 0.001, groups I and II compared with group III). For bilateral adrenalectomy, mean operative times were 205 +/- 71 minutes (group I), 328 +/- 11 minutes (group II), and 422 +/- 77 minutes (group III). Patients who underwent laparoscopic adrenalectomy had significantly less operative blood loss (mean, 104 mL compared to 408 mL in group I and 366 mL in group II, p < 0.001) and a lower incidence of perioperative blood transfusion. Laparoscopic adrenalectomy was also associated with significantly reduced parenteral pain medication requirements (p < or = 0.001) and more rapid resumption of a regular diet (p < or = 0.01) compared to open adrenalectomy. Postoperative length of stay was significantly longer in group I (8.7 +/- 4.5 days) and in group II (6.2 +/- 3.9 days) after open adrenalectomy than after laparoscopic adrenalectomy (3.2 +/- 0.9 days) (p < 0.01). Total hospital charges were similar for groups II and III but somewhat higher for group I. Patients were able to resume 100 percent activity an average of 10.6 +/- 4.9 days after laparoscopic adrenalectomy and returned to work a mean of 16.0 +/- 6.1 days postoperatively. CONCLUSIONS: Laparoscopic adrenalectomy is a safe and effective procedure and has several advantages over open adrenalectomy. Laparoscopic adrenalectomy should become the preferred operative approach for the treatment of patients with small, benign adrenal neoplasms.

Adrenal Gland Neoplasms↗
PubMed1995

Loss of neurofibromatosis type I (NF1) gene expression in pheochromocytomas from patients without NF1.

The neurofibromatosis type 1 (NF1) gene encodes a tumor-suppressor protein termed neurofibromin, which, in adults, is expressed predominantly in neurons, Schwann cells, and the adrenal medulla. Loss of NF1 gene expression has been reported in Schwann cell tumors (neurofibrosarcomas) from patients with NF1 as well as in malignant melanomas and neuroblastomas from patients without NF1. Previously, we demonstrated the lack of neurofibromin expression in six pheochromocytomas from patients with NF1, supporting the idea that neurofibromin might be an essential regulator of cell growth in these cells. To determine whether NF1 gene expression is similarly altered in pheochromocytomas from patients without NF1, we examined 20 pheochromocytomas for the presence of NF1 RNA and neurofibromin by reverse-transcribed polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. Reduced or absent NF1 gene expression was documented in 7 of these 20 tumors (35%) including 1 of 4 sporadic tumors, 3 of 10 tumors from patients with multiple endocrine neoplasia (MEN) 2A, 2 of 4 tumors from patients with MEN2B, and 1 of 2 tumors from patients with von Hippel-Lindau syndrome. In addition, most of these tumors expressed predominantly the type 1 NF1 isoform (75% type 1 NF1 isoform expression) as opposed to other neural crest-derived tissues such as adrenal gland and Schwann cells, which express predominantly type 2 NF1. This type 1 isoform predominance was also observed in the rat pheochromocytoma PC12 cell line, suggesting that this change in isoform expression may be associated with the genesis of these tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗