FOLH1 and sarcoma: The difference in high PSMA expression rate was also evident within specific histological subtypes, for instance, 36% (4/11) of leiomyosarcomas in our study had high PSMA expression, compared to 11% (7/66) of leiomyosarcomas in the cohort of Heitkötter et al. Based on the association between PSMA expression and tumour aggressiveness, also within sarcomas [11], we hypothesise that the increased rates of high PSMA expression in this study stem from the inclusion criteria, which selected only patients who had developed metastatic soft tissue sarcoma.