Aims: High intensity focused ultrasound (HIFU) is an emerging alternative for the treatment of prostate adenocarcinoma. Alpha-methylacyl-CoA racemase (AMACR) has been shown to be a sensitive immunomarker for prostate cancer, however, there is no information available concerning its utility and that of other immunomarkers for the detection of malignancy after HIFU therapy.
Methods: AMACR expression was examined in 11 cases of prostatic carcinoma treated by HIFU, with histological evidence of residual carcinoma. In seven cases tumour was examined from thin core biopsies and in four cases from tissue fragments obtained by transurethral resection of prostate (TURP). In addition to AMACR, immunostaining was also undertaken for p63, cytokeratin 34betaE12, cytokeratin 5, cytokeratin 8-18, prostate specific alkaline phosphatase (PSAP), prostate specific antigen (PSA), chromogranin and CD56.
Results: In two of the cases foci of tumour were cut out in serial sections. AMACR was expressed in eight of nine evaluable cases (4/5 biopsies and 4/4 TURP specimens). Cytokeratin 8-18 and PSAP were positive in all cases, whereas PSA was positive in five of nine cases. Cytokeratin 34betaE12, cytokeratin 5, and p63 marked the basal layer in normal prostatic glands, but were negative in neoplastic glands. In four cases we found tumour cells with positive staining for CD56 and chromogranin.
Conclusions: A panel with positive markers for AMACR, and negative markers for p63/cytokeratin 5/cytokeratin 34betaE12 confirms the neoplastic nature of the residual glands on biopsies or TURP fragments sampled after HIFU therapy.