B2M and Familial prostate cancer: Using C4-2B control and β2-M knockdown prostate cancer cells (KDβ2-M) we tested the levels of stress response proteins such as heat shock protein 27 (HSP27) 17 and heat shock protein 70 (HSP70) 18 and DNA repair enzymes such as N-methylpurine-DNA glycosylase (MPG) 19 and nudix (nucleoside diphosphate linked moiety X)-type motif 1 (NUDT1) 20.