ATM and neoplasm: Baseline tumor analyses of this patients revealed complete absence of ATM protein expression, although there was no evidence of ATM mutation, MMR deficiency (loss of MLH1 and PMS2) and truncating mutations in several DNA repair enzymes, including two heterozygous truncating mutations in ARID1A and heterozygous truncating mutations in CHEK1, RAD50, POLD1 [256].