Loss of heterozygosity of BRCA1, TP53 and TCRD markers analysed in sporadic endometrial cancer.

Genetic alterations of tumour suppressor genes, for which loss of heterozygosity (LOH) is one mechanism of gene inactivation, are important steps in the development of endometrial cancer. To investigate the clinical relevance of LOH of BRCA1 (17q21), TP53 (17p13) and TCRD (14q11) in endometrial cancer, polymerase chain reaction (PCR)-based fluorescent DNA technology for the detection of microsatellite polymorphisms was applied. One hundred and thirteen archival endometrial cancer samples with matched normal tissues were examined. Allele loss at three loci were correlated with age, tumour size, lymph node status, metastases, stage, histological types, grade, expression of oestrogen receptor (ER) and progesterone receptor (PgR), family history of cancer, previous history of cancer or precursor lesions, and previous history of hormone replacement therapy (HRT). LOH for BRCA1 was detected in 18.1%, of TP53 in 26.9%, and of TCRD in 26.3% of informative cases. LOH of BRCA1 correlated with medium grade, positive ER status, and family history of cancer; LOH of TP53 correlated with younger age, high grade, positive PgR status, and with tumours from patients without HRT; LOH of TCRD correlated only with family history of cancer. LOH at all three loci correlated only with grade and positive family history. Allele loss of one of the three tumour suppressor loci did not correlate with disease-free survival (DFS), but LOH of BRCA1 correlated significantly with decreased overall survival (OS). The latter, together with the correlation of LOH of BRCA1 locus with steroid hormone receptor expression, might give a hint to the potential involvement of the co-localised 17 beta-hydroxysteroid dehydrogenase (HSD) gene in the development of endometrial cancer.

int-2 and c-erbB-2 gene amplification detected in 70 frozen human breast carcinomas by quantitative polymerase chain reaction.

Gene amplification is a common mechanism of proto-oncogene activation and contributes to tumor progression. Analysis of such genetic alterations is relevant to our understanding of tumor genetics and can provide prognostic information for the patients. A rapid, non-radioactive approach based on qdPCR and fluorescent DNA technique was applied for determination of int-2 and c-erbB2 gene amplification and correlated with other prognostic factors in 70 breast cancer samples. ER and PgR were analysed by immunohistochemistry. The mixed template assay showed 96% concordance between calculated and measured gene copy number. int-2 gene and c-erbB2 amplification were both found in 24% of the tumors. The amplification did not correlate with any of the other prognostic factors. 8% of the tumors showed amplification of both genes without significant correlations to any of the other parameters. The fd-PCR assay is a valuable tool for determination of amplification of int-2 and c-erbB2 genes. Therefore, more detailed information about individual tumour biology and outcome may be acquired by this routine assay and probably provide prognostic impact.

Clinical impact of detection of loss of heterozygosity of BRCA1 and BRCA2 markers in sporadic breast cancer.

The development of familial and sporadic breast cancer is based on genetic alterations of tumour-suppressor genes, for which loss of heterozygosity (LOH) is one mechanism of gene inactivation. To investigate LOH of BRCA1 (17q21) and BRCA2 (13-q12-13) in sporadic breast cancer, polymerase chain reaction (PCR)-based fluorescent DNA technology for detection of microsatellite polymorphisms was applied. A total of 137 breast cancer and 15 benign breast specimens with matched normal tissue were examined. Fluorescent-labelled PCR products were analysed in an automated DNA sequencer (ALFTM Pharmacia). Losses at both loci were correlated with different histological types, age, tumour size, lymph node status, grading and steroid hormone receptor expression, [SHR: oestrogen receptor (ER), progesterone receptor (PgR)]. For BRCA1 (D17S855, THRA1, D17S579) losses could be detected in invasive ductal carcinoma (IDC; n = 108) in 32-38%, invasive lobular carcinoma (ILC; n = 19) in 21-42% depending on the marker applied, but not in benign breast tumours (n = 15). Losses of BRCA1 markers correlated with larger tumour size, higher grade, and PgR expression. For BRCA2 (D13S260, D13S267, D13S171) losses could be detected in 108 IDCs in 30-38%, in 19 ILCs in 17-39% depending on the marker applied, but not in benign breast tumours. Losses of BRCA2 markers correlated only with higher grade. Microsatellite analyses combined with detection of fluorescent-labelled PCR products by an automated laser DNA sequencer can be used for routine determination of LOH. In sporadic breast cancer, LOH of BRCA1 of BRCA2 does not add decisive prognostic value as stated for familial breast cancer.