Mutant p53 correlates with reduced expression of thrombospondin-1, increased angiogenesis, and metastatic progression in melanoma.

On the basis of reports linking mutant p53 (mp53) to decreased expression of the angiogenesis inhibitor thrombospondin-1 (TSP-1) and increased angiogenesis, we compared primary and metastatic melanoma tumor specimens to determine if these factors were associated with metastatic progression. Western blotting, immunohistochemistry (IHC), and image analysis (IA) techniques were employed to evaluate the relationship between p53 status and TSP-1 expression in Zaz and M14 melanoma cell lines, and among p53, TSP-1, and angiogenesis in primary and metastatic melanomas. Zaz cells expressed wild-type p53 (WT p53) and high levels of TSP-1, while the M14 cells expressed mp53 and low TSP-1 levels. Examination of clinical melanoma specimens (N = 99) revealed an incidence of mp53 of 48%. Specimens with WT p53 (N = 46) expressed significantly higher mean levels of TSP-1 (41 +/- 27 vs. 21 +/- 24; p = 0.0004), and lower microvessel counts per 200x field (25 +/- 17 vs. 40 +/- 20; p = 0.0001) than tumors expressing mp53 (N = 42). A significantly higher incidence of mp53 expression was seen in metastatic tumors (64%, 37/58) than in primary tumors (27%, 11/41)(p < 0.0005). Primary tumors specimens had higher levels of TSP-1 (40 +/- 27 vs. 25 +/- 25; p = 0.0054) and lower microvessel counts (26 +/- 18 vs. 39 +/- 20, p = 0.0013) than metastatic tumors. These data suggest that acquisition of mp53, decreased TSP-1, and increased microvessel infiltration may be interrelated and associated with the metastatic phenotype in malignant melanoma.

Biomarker conservation in primary and metastatic epithelial ovarian cancer.

PURPOSE: The aim of this study was to compare the overexpression of specific biomarkers in primary advanced and recurrent epithelial ovarian cancers. METHODS: Biomarker expression by epithelial ovarian cancer specimens from primary and metastatic sites was examined by immunohistochemistry and flow cytometry. Biomarker expression by subpopulations of tissues consisting of matched pairs of synchronous and metachronous lesions was also studied. RESULTS: A total of 3173 epithelial ovarian cancer specimens were retrieved from women with FIGO Stage III/IV disease. These included lesions from 1036 primary and 2137 metastatic sites. The percentages of biomarker expression for primary and metastatic lesions, respectively, were MDR1, 12 and 10%; p53, 55 and 60%; HER2, 12 and 11%; EGF-R, 26 and 33%; increased microvessel counts (CD31), 21 and 36%. Approximately 73% of both primary and metastatic specimens were aneuploid, and approximately 57% of both sets had an S-phase fraction >7%. Only EGF-R and CD31 expression were found to be significantly different between the primary and metastatic tumors (P < 0.05). Of the paired synchronous cases (n = 48) evaluated, 88% of aneuploid primary lesions were associated with aneuploid metastases. Similarly, the distributions for MDR1, HER2, and p53 expression did not vary significantly between primary and metastatic sites. Pairings of metachronous cases (n = 66) revealed that nearly 80% of primary aneuploid tumors (n = 39) retained their aneuploid status at the time of relapse. Furthermore, there were no significant changes in MDR1, p53, or HER2 expression at relapse. CONCLUSIONS: With the exception of EGF-R and CD31, clonal divergence of the biomarkers evaluated in this study probably does not play a significant role in imparting clinical heterogeneity during the advanced and recurrent stages of epithelial ovarian cancer. These particular genes likely undergo alterations early in the tumorigenesis process before metastases have become established.