RETRACTED ARTICLE: Aberrant promoter methylation of the CHD1 gene may contribute to the pathogenesis of breast cancer: a meta-analysis

Cadherin-1 ( CHD1 ), as an invasion suppressor gene, could suppress tumor cell invasion and metastasis in various tumors, but reduced CHD1 levels, resulting from epigenetic silencing, are common in poorly differentiated, advanced stage carcinomas. This meta-analysis was performed to evaluate the relationships between promoter methylation of CHD1 and breast cancer. Relevant studies were retrieved from the Web of Science (1945 ~ 2013), the Cochrane Library (Issue 12, 2013), PubMed (1966 ~ 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013) using a systematic literature search. Results were summarized by meta-analyses, conducted using the STATA software (version 12.0, Stata Corporation, College Station, TX, USA). Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were calculated. In the present meta-analysis, 9 cohort studies with a total of 425 patients with breast cancer were included. Our meta-analysis results demonstrated that the frequency of CHD1 promoter methylation in cancer tissues was significantly higher than that in normal tissues, adjacent tissues, and benign tissues (cancer tissue vs. normal tissue OR = 30.87, 95 % CI = 16.76 ~ 56.86, P < 0.001; cancer tissue vs. adjacent tissue OR = 23.30, 95 % CI = 12.85 ~ 42.26, P < 0.001; cancer tissue vs. benign tissue OR = 2.94, 95 % CI = 1.60 ~ 5.40, P < 0.001; respectively). Ethnicity-stratified analysis indicated that aberrant CHD1 promoter methylation was strongly correlated with breast cancer among both Asians and Caucasians in the majority of subgroups. Our results suggest that aberrant promoter methylation of the CHD1 gene may have a high frequency in breast cancer tissues. Thus, CHD1 methylation could be correlated with the pathogenesis of breast cancer.