αvß3 imaging can accurately distinguish between mature teratoma and necrosis in 18F-FDG-negative residual masses after treatment of non-seminomatous testicular cancer: a preclinical study.

PURPOSE: We assessed whether imaging α(v)ß(3) integrin could distinguish mature teratoma from necrosis in human non-seminomatous germ cell tumour (NSGCT) post-chemotherapy residual masses. METHODS: Human embryonal carcinoma xenografts (six/rat) were untreated (controls) or treated to form mature teratomas with low-dose cisplatin and all-trans retinoic acid (ATRA) over a period of 8 weeks. In another group, necrosis was induced in xenografts with high-dose cisplatin plus etoposide (two cycles). (18)F-Fluorodeoxyglucose ((18)F-FDG) small animal positron emission tomography (SA PET) imaging was performed in three rats (one control and two treated for 4 and 8 weeks with cisplatin+ATRA). Imaging of α(v)ß(3) expression was performed in six rats bearing mature teratomas and two rats with necrotic lesions on a microSPECT/CT device after injection of the tracer [(99m)Tc]HYNIC-RGD [6-hydrazinonicotinic acid conjugated to cyclo(Arg-Gly-Asp-D-Phe-Lys)]. Correlative immunohistochemistry studies of human and mouse α(v)ß(3) expression were performed. RESULTS: Cisplatin+ATRA induced differentiation of the xenografts. After 8 weeks, some glandular structures and mesenchymal cells were visible; in contrast, control tumours showed undifferentiated tissues. SA PET imaging showed that mature teratoma had very low avidity for (18)F-FDG [mean standardised uptake value (SUV(mean)) = 0.48 ± 0.05] compared to untreated embryonal carcinoma (SUV(mean) = 0.92 ± 0.13) (p = 0.005). α(v)ß(3) imaging accurately distinguished mature teratoma (tumour to muscle ratio = 4.29 ± 1.57) from necrosis (tumour to muscle ratio = 1.3 ± 0.26) (p = 0.0002). Immunohistochemistry studies showed that α(v)ß(3) integrin expression was strong in the glandular structures of mature teratoma lesions and negative in host stroma. CONCLUSION: Imaging α(v)ß(3) integrin accurately distinguished mature teratoma from necrosis following cisplatin-based treatment in human NSGCT xenografts.

Expression of alpha V-associated integrin beta subunits in epithelial ovarian cancer and its relation to prognosis in patients treated with platinum-based regimens.

The aim of the study was to investigate the relationships between the expression of alphav, beta1, beta3, beta5, and beta6, integrin subunits and clinical parameters in ovarian cancers. Ovarian surface epithelium (OSE) from five donors and tumour samples from 39 patients with an epithelial ovarian cancer (39 primary tumours and 21 associated peritoneal metastases) were analysed using immunohistochemistry on paraffin-embedded or frozen tissue sections. The alphav and beta5 integrin subunits were always present in normal OSE and in tumours. beta1 and beta3 subunit expression was significantly less frequent in grade 3 than in grade 1-2 tumours. The proportion of stage IV tumours expressing beta3 was significantly lower as compared to other stages. The beta6 subunit was undetectable in OSE but was expressed in about 40% of primary tumours. For all integrin, there was a strong relationship between the expression in primary tumours and in associated peritoneal metastases. Survival analyses restricted to patients receiving platinum-based chemotherapy did not reveal any relationship between integrin subunit expression and 3-year survival rate, in this limited series of patients. In conclusion, the expression of the various beta integrin subunits was differentially altered in ovarian carcinoma, evocative of complementary roles of alphav integrins during tumour development.