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The liver is a major site of metastasis for human malignancies, yet the factors that regulate tumor cell survival and growth in this organ remain elusive. Previously, we reported that M-27 IGFÀIR murine lung carcinoma cells with ectopic insulin-like growth factor-1 (IGF-I) receptor overexpression acquired a site-specific, liver-metastasizing potential. Gene expression profiling and subsequent RNA and protein analyses revealed that this was associated with major changes to the expression of extracellular matrix (ECM) protein-encoding genes including type III, IV and XVIII collagen genes, and these changes were also observed in the respective tumors in vivo. Because type IV collagen was the most prominently altered ECM protein in this model, we further analyzed its functional relevance to liver metastasis. M-27 cells stably overexpressing type IV collagen a1 and a2 chains were generated and their growth and metastatic properties investigated. We found that these cells acquired a site-selective growth advantage in the liver and this was associated with cell rescue from anoikis in a collagen IV/a2 integrin/FAK-dependent manner and increased responsiveness to IGF-I. Conversely, collagen IV or focal adhesion kinase (FAK) silencing by smallinterfering RNA in highly metastatic tumor cells enhanced anoikis and decreased liver metastases formation. Moreover, analysis of human surgical specimens revealed uniformly high collagen IV expression in 65/65 hepatic metastases analyzed, regardless of tissue of origin, whereas it was variable and generally low in 50/50 primary colorectal carcinoma specimens examined. The results suggest that collagen IV-conveyed signals are essential cues for liver metastasis in diverse tumor types and identify mediators of collagen IV signaling as potential therapeutic targets in the management of hepatic metastases.

BackgroundIn the developed countries, uveal melanoma is the most common primary intraocular malignancy in adults. Little is known about the epidemiological and geographical distribution of uveal melanoma in Canada.MethodsTo determine the incidence patterns and geographical distribution of uveal melanoma cases in Canada, we conducted the first comprehensive, population-based national study of this malignancy across all Canadian provinces and territories during 1992–2010 years. We examined two independent population-based registries: the Canadian Cancer Registry and Le Registre Québécois du Cancer using corresponding International Classification of Diseases for Oncology-3rd edition codes for all histological subtypes of uveal melanoma.ResultsWe report that 2215 patients were diagnosed with uveal melanoma, of which 52.1% were males. The average -annual incidence rate of uveal melanoma in Canada was 3.75 cases per million individuals per year (95% CI 3.60 to 3.91). Overall, we report a steady increase in uveal melanoma incidence with an annual increase of 0.074 cases per million individuals per year. Significant differences in the incidence rates of uveal melanoma between Canadian provinces and territories were noted, where the highest crude incidence was in British Columbia and Saskatchewan with rates of 6.38 and 5.47 cases per million individuals per year, respectively.ConclusionsThis work, for the first time, defines the disease burden of uveal melanoma in Canada and highlights important longitudinal, geographical and spatial differences in the distribution of uveal melanoma in Canada.