Analysis of the distribution of mutation sites within genes revealed the presence of single or multiple hotspot mutations in high-frequency mutation genes (Supplementary Figure S4), such as MC1R: c.359T>C (p.I120T), MLH1: c.1151T>A (p.V384D), PRKDC: c.10681T>A (p.L3561M), ERCC5: c.640C>T (p.R214C), ERCC5: c.767A>G (p.Q256R), PTCH1: c.2222C>T (p.A741V), and RECQL4: c.212A>G (p.E71G), suggesting that these sites were related to the occurrence and progression of ovarian cancer in China. The gene discussed is MLH1; the disease is ovarian carcinoma.