Introduction: Mutations in BRCA1, BRCA2, ATM, TP53, CHK2 and PTEN account for many, but not all, multiple-case breast and ovarian cancer families. The histone acetyltransferase gene EP300 may function as a tumour suppressor gene because it is sometimes somatically mutated in breast, colorectal, gastric and pancreatic cancers, and is located on a region of chromosome 22 that frequently undergoes loss of heterozygosity in many cancer types. We hypothesized that germline mutations in EP300 may account for some breast cancer families that include cases of gastric, pancreatic and/or colorectal cancer.
Methods: We screened the entire coding region of EP300 for mutations in the youngest affected members of 23 non-BRCA1/BRCA2 breast cancer families with at least one confirmed case of gastric, pancreatic and/or colorectal cancer. These families were ascertained in Australia through the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer.
Results: Denaturing HPLC analysis identified a heterozygous alteration at codon 211, specifically a GGC to AGC (glycine to serine) alteration, in two individuals. This conservative amino acid change was not within any known functional domains of EP300. The frequency of the Ser211 variant did not differ significantly between a series of 352 breast cancer patients (4.0%) and 254 control individuals (2.8%; P = 0.5).
Conclusion: The present study does not support a major role for EP300 mutations in breast and ovarian cancer families with a history of gastric, pancreatic and/or colorectal cancer.