PTGS1 (Pfaffl et al. 2003), ACTB (Lee et al. 2006), TP53 (Schwerin et al. 2003) and ETS2 (Zheng et al. 2006) genes were found in mastitis expression studies and murine KO experiments that resulted in increased tumorigenesis of mammary gland and abnormal lactation. This evidence concerns the gene PTGS1 and mastitis.