Tumour-marker levels and prognosis in malignant teratoma of the testis

The effect of 6 putative prognostic factors on survival was studied in patients with Stages III and IV malignant teratoma of the testis. Differences between survival curves were tested for statistical significance. A diameter greater than 5 cm in the largest tumour mass, and greater than 8 pulmonary metastases were adverse prognostic factors (P = 0.004 and 0.008 respectively). Patients with malignant teratoma, trophoblastic, fared worse than those with malignant teratoma, undifferentiated, and malignant teratoma, intermediate (P = 0.011 and 0.023 respectively). Previous chemotherapy or radiotherapy had no significant effect. Serum alpha-foetoprotein (AFP) above 10(3) MRC u/ml and serum beta subunit of human chorionic gonadotrophin (hCG) above 10(5) miu/ml, were found to predict a poor prognosis (P = 0.010 and 0.001 respectively). A combination of measurements of the tumour markers gave the most consistent indication of prognosis, in that patients with either AFP greater than 10(3) MRC u/ml or hCG greater than 10(5) miu/ml, or both, fared much worse than those with neither factor (P = 0.001). Serum concentrations of AFP and hCG should be stated in reports of treatment of testicular teratoma in order to provide a basis for comparison with other series. Regular and frequent measurements of these markers are appropriate throughout the clinical management of patients with malignant teratoma

Measurement of the critical DNA lesions produced by antibody-directed enzyme prodrug therapy (ADEPT) in vitro, in vivo and in clinical material

An antibody-directed enzyme prodrug therapy (ADEPT) system against CEA-positive tumours is currently in phase I clinical trials. It consists of a prodrug, 4-[N,N-bis(2-iodoethyl) amino] phenoxycarbonyl L -glutamic acid (ZD2767P) and a conjugate of the F(ab')2 anti-CEA antibody A5B7 and the bacterial enzyme carboxypeptidase G2 (CPG2). ZD2767P is converted by antibody-targeted CPG2 into an active bifunctional alkylating drug (ZD2767) at the tumour site. The IC 50 value of the prodrug against the human colorectal tumour LS174T cell line was 55 ± 9 μM following a 1 h exposure. In contrast, co-incubation of ZD2767P with CPG2 resulted in 229-fold increase in activity. Using a modified comet assay, DNA interstrand cross links (ISC) were detected within 1 h of ZD2767P + CPG2 treatment and were repaired by 24 h. A clear dose–response was seen between the level of ISC, growth inhibition and ZD2767 concentration. Administration of a therapeutic dose of ZD2767P 72 h after the F(ab′)2 A5B7 conjugate to mice bearing LS147T xenografts resulted in extensive ISC in the tumour after 1 h; repair was seen at 24 h. Tumour biopsies and peripheral lymphocytes were studied in 5 patients on the ADEPT phase I clinical trial. In 4 patients no ISC were detected. These patients also demonstrated poor localization of conjugate and no tumour response was seen. However a significant level of ISC was detected in one tumour biopsy, which also showed evidence of conjugate localization and clinical response. These studies demonstrate the application of the comet assay in the measurement of ISC in vitro and in clinical material and confirm that activation of ZD2767P results in the formation of DNA crosslinks. © 2001 Cancer Research Campaign http://www.bjcancer.co