Biomedical subjects

W Boecker

Publications and source records attributed to W Boecker.

At least 19 recordsLinked to original sources

PubMed2003

Pathological work-up of sentinel lymph nodes in breast cancer. Review of current data to be considered for the formulation of guidelines.

Controversies and inconsistencies regarding the pathological work-up of sentinel lymph nodes (SNs) led the European Working Group for Breast Screening Pathology (EWGBSP) to review published data and current evidence that can promote the formulation of European guidelines for the pathological work-up of SNs. After an evaluation of the accuracy of SN biopsy as a staging procedure, the yields of different sectioning methods and the immunohistochemical detection of metastatic cells are reviewed. Currently published data do not allow the significance of micrometastases or isolated tumour cells to be established, but it is suggested that approximately 18% of the cases may be associated with further nodal (non-SN) metastases, i.e. approximately 2% of all patients initially staged by SN biopsy. The methods for the intraoperative and molecular assessment of SNs are also surveyed.

Breast Neoplasms↗

PubMed2003

Molecular cytogenetic investigations of synchronous bilateral breast cancer.

BACKGROUND: Bilaterality in breast cancer is a rare event and together with an early onset of disease points towards inheritance of the disease. However, most cases seem to occur sporadically, either in a synchronous or metachronous manner. METHODS: Thirty two invasive carcinomas and one in situ carcinoma from 16 patients with synchronous, bilateral breast cancer were investigated by means of comparative genomic hybridisation (CGH) and polymerase chain reaction based multiplex microsatellite analysis. The results were analysed conventionally and were also subjected to a biomathematical cluster analysis. RESULTS: On average, bilateral breast cancer cases showed a low number of genetic alterations, a low frequency of genetic amplifications, and a high rate of chromosomal 16q losses. A distinct, characteristic genetic alteration associated with bilateral breast disease could not be found. Although two tumour pairs appeared to be related using biomathematical processing for microsatellite analysis, this result was reproduced by CGH data processing in one patient only. CONCLUSIONS: Most synchronous, bilateral breast cancer cases seem to represent independent tumours rather than metastatic events. Nevertheless, the possibility of a specific susceptibility remains.

Adult↗

PubMed2003

Demystified...tissue microarray technology.

Several "high throughput methods" have been introduced into research and routine laboratories during the past decade. Providing a new approach to the analysis of genomic alterations and RNA or protein expression patterns, these new techniques generate a plethora of new data in a relatively short time, and promise to deliver clues to the diagnosis and treatment of human cancer. Along with these revolutionary developments, new tools for the interpretation of these large sets of data became necessary and are now widely available. Tissue microarray (TMA) technology is one of these new tools. It is based on the idea of applying miniaturisation and a high throughput approach to the analysis of intact tissues. The potential and the scientific value of TMAs in modern research have been demonstrated in a logarithmically increasing number of studies. The spectrum for additional applications is widening rapidly, and comprises quality control in histotechnology, longterm tissue banking, and the continuing education of pathologists. This review covers the basic technical aspects of TMA production and discusses the current and potential future applications of TMA technology.

Animals↗

PubMed2002

Population-based genetic alterations in Ewing's tumors from Japanese and European Caucasian patients.

BACKGROUND: The incidence of Ewing's tumors (ETs) is lower in Asians or African-Americans than in Caucasians. PATIENTS AND METHODS: Japanese ETs were available for analysis of chromosomal aberrations by comparative genomic hybridization (n = 16) and for expression of chimeric EWS transcripts by reverse-transcriptase polymerase chain reaction (n = 11). These results in Japanese patients were compared with those of 62 ETs in European Caucasian patients registered in the European Intergroup Cooperative Ewing's Sarcoma Study. RESULTS: Japanese patients with ET had lower overall survival (P = 0.0446) and relapse-free survival (P = 0.0371) compared with European Caucasian patients. Ten of 11 Japanese ETs and 31 of 62 European Caucasian ETs had type I (EWS exon 7 to FLI1 exon 6) fusion transcripts. In Japanese ETs, the median numbers of chromosomal aberrations were 2.0 and 6.0 in 11 primary tumors and five relapsed tumors, respectively. In European Caucasian ETs, the median number of changes were 2.5 and 5.0 in 52 primary and 10 relapsed tumors, respectively. Frequent gains were 8q (38%), 8p (31%) and 12q (25%) in Japanese ETs and 8q (52%), 8p (48%) and 12q (19%) in European Caucasian ETs. Frequent losses were 19q (44%), 19p (38%) and 17p (25%) in Japanese ETs and 16q (21%), 19q (18%) and 17p (15%) in European Caucasian ETs. The incidence of losses of 19p (P = 0.0215) and 19q (P = 0.0277) were significantly higher in Japanese ETs than in European Caucasian ETs. An amplification (1p33-p34) was observed in only one Japanese ET. CONCLUSIONS: Japanese patients with ET in this study had a worse prognosis than European Caucasian patients. In molecular genetic analyses, Japanese ETs had a higher frequency of loss of chromosome 19 than European Caucasian ETs. Different genetic aberrations may explain the different incidences and prognoses of ET between Caucasian and Japanese patients.

Adolescent↗

PubMed2002

Tissue microarrays: a new approach for quality control in immunohistochemistry.

AIMS: To improve the interpretation of immunohistochemistry (IHC) staining results the use of a tissue microarray technique was established in a routine setting. METHODS: A tissue microarray was constructed by harvesting 600 microm tissue cores from paraffin wax embedded samples available in a routine pathology department. The punches originating from non-tumorous tissue were placed on host paraffin wax blocks. The microarray contained 12 different tissue samples, with a wide antigen profile and a dimension of 3.5 x 3 mm. One section of the multitissue array was placed as an "internal" positive control on each slide of the patient tissue to undergo identical immunohistochemical procedures. RESULTS: Using the tissue microarray technique as a tool for internal quality control, the interpretation of immunohistochemical staining of more than 20 different antigens in routine IHC was improved. The tissue microarray did not influence the staining results in conventional IHC or in different automated IHC settings. CONCLUSION: The regular use of an institution adapted tissue microarray would be useful for internal positive control in IHC to enable different laboratory demands. Furthermore, this technique improves the evaluation of staining results in IHC.

Antigens↗

PubMed2001

Alternative lengthening of telomeres is associated with chromosomal instability in osteosarcomas.

Telomere maintenance is regarded as a key mechanism in overcoming cellular senescence in tumor cells and in most cases is achieved by the activation of telomerase. However there is at least one alternative mechanism of telomere lengthening (ALT) which is characterized by heterogeneous and elongated telomeres in the absence of telomerase activity (TA). We evaluated the prevalence of TA, gene expression of telomerase subunits and ALT in relation to telomere morphology and function in matrix producing bone tumors and in osteosarcoma cell lines and present evidence of a direct association of ALT with telomere dysfunction and chromosomal instability. Telomere fluorescence in situ hybridization (T-FISH) in ALT cells revealed elongated and shortened telomeres, partly in unusual configurations and loci, dicentric marker chromosomes and signal-free chromosome ends. Free ends give rise to end-to-end associations and may induce breakage-fusion-bridge cycles resulting in an increased number of complex chromosomal rearrangements, as detected by multiplex-FISH (M-FISH). We propose that ALT cannot be seen as an equivalent to telomerase activity in telomere maintenance. Its association with telomere dysfunction and chromosomal instability may have major implications for tumor progression.

Adult↗

PubMed2001

Distal chromosome 17 gains in neuroblastomas detected by comparative genomic hybridization (CGH) are associated with a poor clinical outcome.

PROCEDURE: To establish the significance of chromosome 17 aberrations in the biology of neuroblastomas, the fresh-frozen material of 53 primary neuroblastomas (average patient age: 20.8 months; stage 1 or 2: n = 10; stage 3: n = 10; stage 4: n = 10; stage 4s: n = 23) was studied by means of comparative genomic hybridization (CGH). Follow-up data were available for 52 of 53 cases studied (average follow-up period: 26.4 months). Except for one, all cases had previously been analyzed for MYCN status (semiquantitative Southern blot analysis). Studies of LOH 1p36 (VNTR-PCR) had been performed on 28 of 53 cases. RESULTS: Chromosome 17 gains were detected in 46 of 53 (86.8%) cases. Whole chromosome gains were mostly restricted to localized tumors (stage 1 or 2: 9 of 10 cases; stage 4s:19 of 23; stage 3: 2 of 10; stage 4:0 of 10 cases), whereas distal 17 gains were significantly associated with clinically advanced tumor stages and patients aged over 1 year at diagnosis. Univariate analyses revealed a statistically significant correlation of distal 17q gains with overall survival (P< 0.01, MYCN amplification: P< 0.01; 1p deletion: P< 0.01) and an elevated recurrency rate (17q: P= 0.02, MYCN amplification: P = 0.05; 1p deletion P= 0.3). There was a strong coincidence of distal 17q gains and 1p deletion or MYCN amplification (P < 0.01). CONCLUSION: Our data indicate that distal chromosome 17q gains are of major prognostic relevance for neuroblastoma patients. However, studies on a larger series of tumors have to be performed to assess whether or not these alterations are independent prognostic markers of a poor clinical outcome.

Child↗

PubMed2001

Monoclonality in normal epithelium and in hyperplastic and neoplastic lesions of the breast.

The clonal nature of neoplastic lesions such as invasive breast cancer and ductal carcinoma in situ (DCIS) has been widely proven by several proliferative, genetic or other malignancy-associated markers. The aim of this study is to clarify whether benign hyperplastic lesions such as ductal hyperplasia of usual type (DH) and papilloma can be distinguished from neoplastic lesions such as DCIS by X-chromosome inactivation analysis. Clonal analysis was performed using a polymerase chain reaction-based assay for non-random X-chromosome inactivation of the human androgen receptor gene (HUMARA). Formalin-fixed and paraffin-embedded archival tissue of ten DCIS, sixteen DH, nine papillomas, and seven normal terminal ductal lobular units (TDLUs) was laser-microdissected to avoid contamination with surrounding tissue. All of the cases analysed revealed a monoclonal origin. Furthermore, in one of these cases, opposite X chromosomes were inactivated within the same breast. X-linked inactivation analysis clearly demonstrates that, at least in the breast, monoclonality is not restricted to neoplastic processes. The data support the hypothesis that the mammary gland is organized into distinct stem cell-derived monoclonal patches and that TDLUs are monoclonal in origin. Any proliferative lesion arising within such a pre-existing clonal patch should therefore be clonal, irrespective of whether it originates from one or more patch cells. Thus, X-chromosome inactivation analysis cannot be considered a valid method for distinguishing between neoplastic and hyperplastic breast lesions.

Breast↗

PubMed2001

Genetic imbalances revealed by comparative genomic hybridization in Ewing tumors.

Ewing tumors are characterized by reciprocal translocations involving the EWS gene on 22q12 fused to ETS transcription-factor family members. Little is known about further aberrations contributing to tumor development and progression. Sixty-two frozen tumors with known EWS rearrangements (52 primary tumors, 10 relapses) of ET patients registered in the EICESS protocol were analyzed by comparative genomic hybridization (CGH). The median number of changes in 52 primary and 10 relapsed cases was 2.5 and 5.0 per tumor (P = 0.153). Frequent abnormalities included gains of chromosomes 8, 12, 20, and 1q and losses of 16q and 19q. Neither number nor type of aberration was associated with histology, tumor size, disease stage, tumor localization, or histologic tumor response to chemotherapy. Among the 52 primary tumors, 26 with Type I fusion (EWS exon 7 to FLI1 exon 6) and 26 with other fusion types had a median of 2.0 and 3.0 aberrations per tumor, respectively (P = 0.031). Combinations of gains of chromosomes 8 and 12, gains of chromosome 20, and either gains of 8q or 18q and losses of 16q and 17p frequently occurred. The cumulative overall survival (OAS) was different between 35 patients with <5 aberrations and 13 patients with > or =5 aberrations (P = 0.009). Univariate analysis showed that patients with gains of 1q, 2q, 12, and 20 or losses of 16q and 17p had significantly lower OAS than those without aberrations. By multivariate analysis, loss of 16q (relative risk [RR] = 5.3; P = 0.0006) was an independent prognostic factor.

Adolescent↗

PubMed2001

Ductal invasive G2 and G3 carcinomas of the breast are the end stages of at least two different lines of genetic evolution.

Ductal invasive grade (G) 2 and G3 carcinomas represent the majority of invasive breast cancers. Previous morphological and cytogenetic studies have provided evidence that ductal invasive G2 carcinoma may originate from at least two different genetic pathways. The aim of this study was to evaluate further the heterogeneity of G2 breast cancer in comparison with G3 cancers by cytogenetic and quantitative analysis. To this end, 35 cases of ductal invasive G2 and 42 cases of ductal invasive G3 carcinomas were investigated by means of comparative genomic hybridization (CGH) and these findings were correlated with DNA ploidy status, mitotic activity index (MAI), mean nuclear area (MNA), volume per lumen (VPL), and clinico-pathological parameters. The findings of this study demonstrate that ductal invasive G2 carcinomas, in contrast to ductal invasive G3 carcinomas, have to be interpreted as the morphological end stage resulting from two different cytogenetic and morphological pathways; the loss of 16q material is the cytogenetic key event in the evolution of a subgroup of this entity. By correlating genetic alterations with DNA ploidy status, an extended morphology-based cytogenetic progression model is presented, with early and late genetic alterations in the pathogenesis of breast cancer. The correlation with MAI gives rise to the hypothesis that these different genetic pathways significantly differ in their proliferation rate. Further studies will be required to elucidate which genes contribute to an altered proliferation rate in these subgroups and to the associated prognosis.

Breast Neoplasms↗

PubMed2001

Ductal epithelial proliferations of the breast: a biological continuum? Comparative genomic hybridization and high-molecular-weight cytokeratin expression patterns.

According to current concepts, benign proliferative breast disease (BPBD) is a direct precursor of breast cancer, in a spectrum ranging from ductal hyperplasia to overtly invasive carcinoma. In this study, comparative genomic hybridization (CGH) was used to screen ductal hyperplasia and other BPBD lesions and ductal carcinoma in situ (DCIS) for common genomic abnormalities, to test the relationship between these hyperplastic and neoplastic lesions. Immunohistochemistry for cytokeratin 5/6 was used as a diagnostic adjunct to distinguish ductal hyperplasia from DCIS. A total of 42 cases of BPBD comprising ductal hyperplasia of the usual type (n=14), papilloma (n=22), tubular adenoma (n=3), and adenosis (n=3), as well as 52 cases of DCIS, were studied. All cases of BPBD consistently displayed the presence of a subpopulation of cytokeratin 5/6-expressing basal-type cells within the proliferative lesion, whereas all of the non-high-grade and most of the high-grade DCIS lesions lacked cytokeratin 5/6-positive cells. Whereas gross genomic alterations, as determined by CGH, were undetectable in BPBD, distinct genetic changes characterized all cases of DCIS, with one exception. These results confirm the usefulness of cytokeratin 5/6 immunohistology in the diagnosis of BPBD and neoplastic breast lesions and support the view that BPBD and DCIS are not closely related entities and that BPBD is not an obligate direct precursor of DCIS.

Adenoma↗

PubMed2001

Genetic characterisation of invasive breast cancer: a comparison of CGH and PCR based multiplex microsatellite analysis.

AIMS: Comparative genomic hybridisation (CGH) is a reliable tool to gain an overview of all unbalanced chromosomal alterations within a tumour. Nevertheless, the high numbers of tumour cells required and the comparatively low resolution are drawbacks of this technique. Polymerase chain reaction (PCR) based multiplex microsatellite analysis represents a semi-automated, highly reproducible method, which requires small amounts of tumour cells. This is a comparative study of CGH and microsatellite analysis. METHODS: Eighty one samples of invasive breast cancer were investigated by two sensitive multiplex PCRs containing three microsatellites each of six markers (D6S261, D11S907, D6S300, D11S927, D8S272, and D11S925), and two additional microsatellite markers located within intron 1 of the epidermal growth factor receptor gene (egfr) and p53 (p53CA). RESULTS: At least one example of loss of heterozygosity was detectable in all breast cancer tissues. However, the overall rate of accordance between the two methods tested was only 61%. An increasing rate of the number of genetic alterations in each case was mirrored by a constantly increasing fractional allelic loss index. CONCLUSIONS: PCR based multiplex microsatellite analysis using this panel of eight microsatellite markers not only enables the characterisation of cells that have malignant potential in a high frequency of patients with breast cancer, but can also give an estimate of the degree of genetic progression.

Breast Neoplasms↗

PubMed2000

Length and loss of heterozygosity of an intron 1 polymorphic sequence of egfr is related to cytogenetic alterations and epithelial growth factor receptor expression.

Overexpression of epithelial growth factor receptor (EGFR) is correlated with a poor prognosis and reduced steroid receptor expression. Recently, it was demonstrated that the length of a CA repeat in the intron 1 of EGFR correlated with the expression of EGFR in vitro. We investigated 112 cases of cancerous and noncancerous breast tumor samples for loss of heterozygosity (LOH) in intron 1 of the egfr gene and determined the intratumoral EGFR content and genetic alterations by comparative genomic hybridization. Heterozygous tumors with short CA repeats showed elevated EGFR expression in contrast to tumors with longer CA repeats. Tumors with LOH in intron 1 of egfr revealed higher EGFR expression when the longer allele was lost compared with loss of the shorter allele. Additionally, tumors with a loss of the long allele showed more chromosomal alterations, especially a higher frequency of amplifications. We conclude that the CA repeat status in intron 1 of the egfr gene also modulates the intratumoral EGFR content in vivo. Furthermore, LOH at the CA repeat is associated with genetically advanced tumors. Therefore, allele-specific gene expression due to LOH of the CA repeat could be assumed to be an important event in invasive breast cancer development.

Alleles↗

PubMed2000

Telomerase is a strong indicator for assessing the proneness to progression in neuroblastomas.

BACKGROUND: As traditional parameters do not ensure completely accurate prognostic grouping in neuroblastoma (NB), new molecular markers are needed for assessing the individual patient's prognosis more precisely. PROCEDURE, RESULTS, AND CONCLUSIONS: Based on 133 NB, we show that telomerase activity (TA) is a powerful, independent prognostic marker for all stages and is capable of differentiating between good and poor outcome in putative 'favorable' clinical or biological subgroups of NB patients. Analysis of gene and protein expression of telomerase subunits suggests that the presence or absence of TA in NB is strongly correlated with expression levels of both the catalytic subunit hTERT and the internal RNA component (hTR).

Disease Progression↗

PubMed2000

Causes of inconsistency in diagnosing and classifying intraductal proliferations of the breast. European Commission Working Group on Breast Screening Pathology.

It is now widely recognised that classifying ductal carcinoma in situ (DCIS) of the breast and diagnosing atypical ductal hyperplasia are associated with significant interobserver variation. Two possible reasons for this inconsistency are differences in the interpretation of specified histological features and field selection where morphology is heterogeneous. In order to investigate the relative contribution of these two factors to inconsistent interpretation of intraductal proliferations, histological sections of 32 lesions were sent to 23 European pathologists followed 3 years later by images of small parts of these sections. Kappa statistics for diagnosing hyperplasia of usual type, atypical ductal hyperplasia and ductal carcinoma in situ were 0.54, 0.35 and 0.78 for sections and 0.47, 0.29 and 0.78 for images, respectively, showing that most of the inconsistency is due to differences in morphological interpretation. Improvements can thus be expected only if diagnostic criteria or methodology are changed. In contrast, kappa for classifying DCIS by growth pattern was very low at 0.23 for sections and better at 0.47 for images, reflecting the widely recognised variation in the growth pattern of DCIS. Higher kappa statistics were obtained when any mention of an individual growth pattern was included in that category, thus allowing multiple categories per case; but kappa was still higher for images than sections. Classifying DCIS by nuclear grade gave kappa values of 0.36 for sections and 0.49 for images, indicating that intralesional heterogeneity has hitherto been underestimated as a cause of inconsistency in classifying DCIS by this method. More rigorous assessment of the proportions of the different nuclear grades present could lead to an improvement in consistency.

Breast↗

PubMed2000

Cytokeratin 5/6 immunohistochemistry assists the differential diagnosis of atypical proliferations of the breast.

AIMS: This study was performed to determine the diagnostic value of keratin 5/6 (CK 5/6) immunophenotyping on routinely processed breast tissues. METHODS AND RESULTS: Six hundred and ninety-nine breast lesions, including normal tissues as well as benign and malignant lesions in 321 formalin-fixed, paraffin-embedded samples from 158 different patients were investigated immunohistochemically, following wet autoclave pre-treatment for antigen retrieval. In normal breast tissues, both myoepithelial and luminal epithelial cells expressed CK 5/6 in varying amounts. While myoepithelial immunoreactivity was most pronounced in the duct system, luminal epithelial immunoreactivity was strongest in the terminal duct lobular units. In ductal hyperplasias (DH), luminal epithelial cells predominantly revealed CK 5/6 immunoreaction. In contrast, neoplastic epithelial cells in atypical ductal and lobular hyperplasias (ADH and ALH) lacked such an expression, whereas in ductal in-situ carcinomas (DCIS) and in infiltrating ductal carcinomas 3.7% and 7.7%, of the cases respectively, showed positive immunostaining for CK 5/6. CONCLUSIONS: Immunophenotyping of keratin 5/6 expression can be helpful in the diagnosis of atypical hyperplasias and in-situ carcinomas of the breast. It is particularly valuable in the differential diagnosis between benign and atypical proliferative lesions.

Breast↗

PubMed2000

Comparative methodological analysis of erbB-2/HER-2 gene dosage, chromosomal copy number and protein overexpression in breast carcinoma tissues for diagnostic use.

AIMS: This study was performed to test the validity of different methods for determining the status of the erbB-2/HER-2 oncogene in breast cancer tissues for diagnostic use. METHODS AND RESULTS: Forty formalin-fixed, paraffin-embedded breast carcinomas were investigated by fluorescence in situ and comparative genomic hybridization (FISH, CGH) as well as by immunohistochemistry (IHC) using Dako-HercepTest and CB11 antibody (Ventana). Additionally, competitive-differential polymerase chain reaction (cdPCR) was performed on frozen samples to estimate gene dosage alterations of erbB-2/HER-2. Amplification was detected in 12-23% and protein overexpression in 16-68% of the cases, depending on the methodology and/or the reagent used. Perfect concordance (100%) was found between the results of cdPCR and CB11-IHC, and a 97% concordance between FISH and CB11-IHC. The concordance between Dako-HercepTest and CB11-IHC was 78%: seven of eight 2+ carcinomas with the Dako-HercepTest were classified as nonamplified using FISH. CONCLUSIONS: Our results indicate that high-level expression as well as normal erbB-2/HER-2 status of breast carcinomas can be detected reliably both by IHC and gene dosage assessment in paraffin material for diagnostic use. However, borderline results, especially those with 2 + immunopositivity, should be interpreted with caution and increased emphasis should be given to other clinical and prognostic information available.

Adenocarcinoma↗

PubMed2000

Telomerase activity and telomerase subunits gene expression patterns in neuroblastoma: a molecular and immunohistochemical study establishing prognostic tools for fresh-frozen and paraffin-embedded tissues.

PURPOSE: We have recently demonstrated that telomerase activity (TA) is an independent prognostic factor in neuroblastomas. In the present study, the prognostic impact of TA and gene expression of the three major telomerase subunits is evaluated by molecular and immunohistochemical techniques in fresh-frozen and paraffin-embedded tissues. PATIENTS AND METHODS: One hundred thirty-three neuroblastomas of all stages were analyzed for TA. The TA levels of 75 neuroblastoma cases were correlated with gene expression of telomerase subunits hTRT, human telomerase RNA (hTR), and telomerase protein 1 (TP1) by quantitative reverse transcriptase polymerase chain reaction (RT-PCR), using an innovative approach on the LightCycler instrument (Roche Diagnostics, Mannheim, Germany). For selected cases, the applicability of RT-PCR and immunohistochemistry for hTRT expression analysis was investigated in paraffin-embedded tissues. TA and subunit expression patterns were correlated with traditional prognostic indicators and disease outcome. RESULTS: TA was present in a total of 39 (29.3%) of 133 neuroblastomas and in 31 (29.8%) of 104 initial neuroblastomas without cytotoxic pretreatment. TA was significantly correlated with both event-free and overall survival (P <.0001). Furthermore, we found a significant correlation between expression levels of TA and hTRT (P <.0001) as well as hTR (P <.001). Multivariate analysis revealed only TA and tumor stage but not serum lactate dehydrogenase, MYCN amplification, or age at diagnosis as independent prognostic factors. CONCLUSION: The significant correlation with clinical outcome strongly recommends that analysis of TA be incorporated into the clinical investigation of each individual neuroblastoma at the time of diagnosis. Because the mere presence or absence of TA without further quantification is sufficient basis for predicting disease outcome, the telomeric repeat amplification protocol assay could be complemented with but not replaced by analysis of hTRT or hTR expression.

Biomarkers, Tumor↗