Phenotypic analysis of mice carrying null mutations in two of the most widely expressed HAT/DESC subfamily genes, Tmprss11a and Tmprss11d, did not reveal an effect of the loss of either of the genes on development, postnatal growth or long-term health, although prostate hyperplasia was seen only in Tmprss11a−/− males, and the incidence of lymphoma was lower in Tmprss11d+/+ females in small cohorts of older animals subjected to detailed histopathological examination. This evidence concerns the gene TMPRSS11A and lymphoma.