STK31 and breast cancer: These genes included KLRD1, S100A12, EPHA5, SFRP2, FZD2, STK31, and PCDH15. We selected genes involved in the Wnt singling pathway, which is known to contribute to breast cancer progression Frizzled receptors (FZD2), secreted frizzled-related protein 2 (SFRP2), and genes that only expressed during certain physiological changes such spermatogenesis, serine/threonine kinase 31 (STK31), and lactation, alpha-lactalbumin (LALAB).