BRCA1 and breast cancer: In line with these results in osteosarcomas, the expression pattern of the DDR molecules PARP1, γH2AX, BRCA1, and/or BRCA2 have been associated with the progression of various cancers, such as gastric cancer [28], breast cancer [29], ovarian cancer [28, 30], glioblastoma [31], and chordoma [32].