PKD1L2 and breast cancer: rs386792906 (chr16:g.81253642 AG>TC) in polycystin 1 like 2 (PKD1L2), which was associated with resistance to MTX, showed the strongest association of the nine tested anti-cancer drugs among the breast cancer subgroup (P = 1.52 × 10−5, rs = 0.991, Table 11).