HIC1 promoter methylation and 17p13.3 allelic loss in invasive ductal carcinoma of the breast

The HIC1 gene is a transcriptional regulator commonly methylated in a variety of human cancer. Thirty-three invasive ductal carcinomas of the breast and 21 matched normal breast tissues were analysed for HIC1 promoter methylation, and allelic loss of a 700 kb region spanning the gene locus. At least one genetic or epigenetic abnormality was found in 27 of the carcinomas tested (82%). Promoter methylation was demonstrated in 21 carcinomas (64%), and nine normal tissues (43%), whereas 18 malignant tumors (54%) showed allelic loss. Concomitant loss of heterozigosity and promoter hypermethylation in the region spanning HIC1 was detected in eight carcinomas (24%) suggesting that in this subset of tumors both copies of the gene are functionally lost. These observations support a role for the HIC1 gene in the pathogenesis of breast ductal carcinomas. q 2004 Elsevier Ireland Ltd. All rights reserved

Aberrant genes promoter methylation in neural crest-derived tumors.

Disturbances in the epigenetic landscape by aberrant methylation of CpG islands can lead to inactivation of cancer-related genes in solid tumors. We analyzed the promoter methylation status of 6 genes previously reported as cancer-specific methylated (MCAM, SSBP2, NISCH, B4GALT1, KIF1A and RASSF1A) in 38 neural crest-derived tumors by quantitative methylation-specific real-time PCR (QMSP). The results demonstrated that the determination of the methylation status of RASSF1A is able to distinguish between normal and tumor samples in cutaneous melanomas, lung carcinoids and small bowel carcinoids. MCAM methylation levels were significantly higher in lung carcinoids tumors (p=0.001), suggesting that this alteration may represent a molecular biomarker in this tumor type

Frequent epigenetics inactivation of KEAP1 gene in non-small cell lung cancer

The KEAP1/Nrf2 pathway is a master regulator of several redox-sensitive genes implicated in resistance of tumor cells against chemotherapeutic drugs. Recent data suggest that epigenetic mechanisms may play a pivotal role in the regulation of KEAP1 expression. We performed a comprehensive genetic and epigenetic analysis of the KEAP1 gene in 47 non-small cell lung cancer tissues and normal specimens. Promoter methylation analysis was performed using a quantitative methylation specific PCR assay in real time. Methylation at the KEAP1 promoter region was detected in 22 out of the 47 NSCLCs (47%) and in none of the normal tissues analyzed. Somatic mutations were detected in 7 out of the 47 tumors (15%) and loss of heterozygosity (LOH) in 10 out of the 47 (21%) of the cases. Overall, we found at least one molecular alteration in 57% of the cases. Approximately one third of the tumors had two alterations and this feature was associated with higher risk of disease progression in univariate COX regression analysis (HR = 3.62; 95% CI 1.24-10.65, p = 0.02). This result was confirmed by Kaplan-Meier analysis, which demonstrated an association between worst outcome and KEAP1 double alterations (p = 0.01, Log rank test). Our results further suggest that deregulation of the NRF2/KEAP1 system could play a pivotal role in the cancerogenesis of NSCLC. In addition identifying patients with KEAP1 genetic and epigenetic abnormalities may contribute to disease progression prediction and response to therapy in lung cancer patients

Changes in CpG islands promoter methylation patterns during ductal breast carcinoma progression

Aberrant promoter methylation of several known or putative tumor suppressor genes occurs frequently during carcinogenesis, and this epigenetic change has been considered as a potential molecular marker for cancer. We examined the methylation status of nine genes (APC, CDH1, CTNNB1, TIMP3, ESR1, GSTP1, MGMT, THBS1, and TMS1), by quantitative methylation specific PCR. Synchronous preinvasive lesions (atypical ductal hyperplasia and/or ductal carcinoma in situ) and invasive ductal breast carcinoma from 52 patients, together with pure lesions from 24 patients and 12 normal tissues paired to tumor and 20 normal breast distant from tumor were analyzed. Aberrant promoter methylation was detected in both preinvasive and invasive lesions for genes APC, CDH1, CTNNB1, TIMP3, ESR1, and GSTP1. However, hierarchical mixed model and Generalized Estimating Equations model analyses showed that only APC, CDH1, and CTNNB1 promoter regions showed a higher frequency and methylation levels in pathologic samples when compared with normal breast. Whereas APC and CTNNB1 did not show differences in methylation levels or frequencies, CDH1 showed higher methylation levels in invasive tumors as compared with preinvasive lesions (P < 0.04, Mann-Whitney test with permutation correction). The analysis of APC, CDH1, and CTNNB1 methylation status was able to distinguish between normal and pathologic samples with a sensitivity of 67% (95% confidence interval, 60-71%) and a specificity of 75% (95% confidence interval, 69-81%). Our data point to the direct involvement of APC, CDH1, and CTNNB1 promoter methylation in the early stages of breast cancer progression and suggest that they may represent a useful tool for the detection of tumor cells in clinical specimen