CYP17A1 and neoplasm: Additionally, transcripts encoding steroidogenic enzymes (Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b1, Hsd17b3, Cyp19a1) and protein (CYP11A1) found in adult Leydig cells were elevated in both Inha KO TAT and tumour regions when compared to Inha KO ‘normal’ tubules, leading us to suggest cells in these regions acquire an atypical steroidogenic phenotype.