CYP27B1 and neoplasm: CYP1 analysis of TCGA-BRCA RNAseq data revealed CYP1A2 expression to be very low (max TPM = 1.3 with a median TPM = 0), while expression of CYP1A1 was high in a subset of tumours (max TPM = 78.3 but median TPM = 0.04) and CYP1B1 was generally more abundant (max TPM = 1611.7 and median TPM = 31.9).