The wild type QPY genotype was associated with an increased incidence of Epstein-Barr-virus-associated hemophagocytic lymphohistiocytosis (HLH) in children.[32] Conversely, a subsequent study reported an association of the mutant RAH genotype with the incidence of breast cancer.[33] However, to link the genetic susceptibility of granzyme B to disease based on the presented data is difficult, because no patient developed HLH or breast cancer following HSCT in the current cohort. This evidence concerns the gene RAB34 and breast cancer.