The Association of Thymidine Phosphorylase with Gastric Cancer Prognosis.

BACKGROUND: Thymidine phosphorylase(TP)plays an important role in angiogenesis and solid tumor invasion. This study aimed to investigate TP expression in gastric cancer(GC), its correlation with clinicopathological features, and its prognostic significance. METHODS: Clinical data and tumor specimens were retrospectively collected from patients with GC in Ikeda Municipal Hospital between January 2005 and December 2006. Tumor specimens were immunohistochemically analyzed for TP expression graded as 0, 1+, 2+, or 3+ and divided into low(0/1+)and high(2+/3+)TP expression groups. To determine its potential prognostic value, any correlation between TP expression and the clinicopathological features of the patients was statistically assessed. RESULTS: Among 111 patients with GC, 33 had high TP expression(29.7%)and 78 had low TP expression(70.3%). There were significant differences in tumor size, tumor depth, venous invasion, lymphatic invasion, and clinical stage between the two groups. Analysis of the Kaplan-Meier survival curves revealed that the high TP group had significantly shorter overall survival(OS; p<0.01)and progression-free survival(PFS; p<0.01)than the low TP group. Moreover, the high TP group had significantly shorter OS(p=0.040)and a trend toward a shorter PFS(p=0.064) than the low TP group in patients with stage Ⅱ, Ⅲ, and Ⅳ cancer. Multivariate analysis revealed that high TP expression was significantly associated with tumor size, tumor type, and lymphatic invasion in patients with GC. CONCLUSIONS: Our results suggest that high TP expression might predict poor prognosis in GC.

Heavily melanotic perivascular epithelioid clear cell tumor of the kidney.

A black-colored and well-circumscribed renal tumor in a 71-year-old woman is reported. The tumor was unique in that it was rich in vasculature and exclusively composed of perivascular epithelioid clear cells. Morphological features were reminiscent of conventional renal cell carcinoma (RCC). However, immunohistochemical examinations showed that the tumor cells did not express any epithelial markers, but diffusely and intensely expressed a melanocytic marker, gp-100/HMB-45. Another striking feature of the tumor was a large amount of cytoplasmic pigment that made the tumor wholly black. The pigment was not stained with Berlin-blue, completely bleached with potassium permanganate, and stained with Fontana-Masson staining, which suggests that the pigment was melanin. Morphological features and immunohistochemical findings indicated that the present tumor was an extreme example of a perivascular epithelioid clear cell tumor with a large amount of melanin, which has not been previously reported. One should be aware of the pure form of perivascular epithelioid clear cell tumor of the kidney because it is sometimes very difficult to differentiate this tumor from conventional RCC. Immunohistochemical examinations and the presence of cytoplasmic melanin can help the differentiation.