NTHL1 and breast cancer: A case–case analysis of cancer incidence in the families of individuals harboring heterozygous NTHL1 LoF variants found no statistically significantly elevated incidence of colorectal cancer, female breast cancer, male breast cancer or ovarian cancer when compared to the NTHL1 wild-type families, although the number of available NTHL1 families was small and the statistical power was limited (Table 2).