TP53 and Decreased total neutrophil count: Regarding bone marrow function, MDM2 SNP309 and TP53 Arg72Pro have been linked to febrile neutropenia in breast cancer patients receiving a combinatorial 5FU/epirubicin/cyclophosphamide (FEC) regimen, with those patients harboring the SNP309GG genotype having a lower incidence of severe neutropenia when receiving treatment in the highest dose range [26].