Aims: CD30 has been shown to be consistently strongly expressed in embryonal carcinomas. Our aim was to examine changes in CD30 expression in embryonal carcinomas before and after treatment with chemotherapy.
Methods and results: One hundred and eighteen retroperitoneal lymph node dissections from patients with metastatic germ cell tumours were reviewed. Seventeen contained embryonal carcinoma deposits. In nine cases, the matching pre-chemotherapy orchidectomy specimens were available. The cases were immunohistochemically stained for CD30. All nine pre- chemotherapy orchidectomy specimens showed embryonal carcinoma and stained strongly positively for CD30. However, only four out of nine of the matched post-chemotherapy retroperitoneal lymph node dissection specimens and a total of six out of 17 (35%) with embryonal carcinoma deposits stained for CD30. Ten seminomas were negative for CD30. Loss of CD30 did not appear to influence the relapse rate of the patients.
Conclusions: Loss of CD30 expression occurs frequently in metastatic embryonal carcinomas after chemotherapy. This finding has implications in the use of CD30 in the diagnosis of metastatic non-seminomatous germ cell tumours and suggests that chemotherapy may alter the immunophenotype of embryonal carcinoma while retaining its characteristic histological appearances.