According to Pinto et al., the 3-year event-free survival of rhabdomyosarcoma patients after vincristine/actinomycin/cyclophosphamide (VAC) therapy was not related to any SNVs in drug-metabolizing enzymes, including CYP2B6 and CYP2C19, whereas Labib et al. revealed favourable therapeutic outcomes in patients carrying the CYP2B6 K262R variant with the same malignancy and therapy protocol54,86. Here, CYP2C19 is linked to rhabdomyosarcoma.