We performed targeted deep sequencing using a massively parallel sequencer for 21 genes known to be associated with hereditary predispositions for pancreatic, breast, and ovarian cancers, namely, ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MLH1, MRE11, MSH2, MSH6, MUTYH, NBN, PALB2, PMS1, PMS2, PTEN, RAD50, RAD51C, STK11, and TP53. The unique sequence depth was 714.1× on average (range, 502.8× – 1126.1×). Here, ATM is linked to ovarian cancer.