Regardless of the histologic site of origin, however, high overexpression of the c-erbB2 gene provides support for the notion that trastuzumab (Herceptin), a humanised anti-HER-2/Neu antibody that is showing great promise for treatment of metastatic breast cancer patients overexpressing HER-2/Neu protein (Slamon et al, 2001), may be a novel, potentially highly effective therapy against this aggressive variant of serous papillary carcinomas. The gene discussed is ERBB2; the disease is papillary serous cystadenocarcinoma.