Four BC-associated variants in HCAR2 were identified, including one frameshift, HCAR2 c.1086_1090del (p.P363Nfs*26) (Table 3 and Fig. 4), and three missense variants, HCAR2 c.424C > T (p.R142W), HCAR2 c.517_518delinsAC (p.G173T), and HCAR2 c.1036A > G (p.M346V) (Table 3 and Figs. 2B). This evidence concerns the gene HCAR2 and breast cancer.