High labeling indices of cdc25B is linked to progression of gastric cancers and associated with a poor prognosis.

To clarify the significance of cdc25B, which plays an important physiologic role in regulation of the G2/M check point, in progression of gastric cancer, 125 samples of paraffin-embedded gastric cancers were investigated by immunohistochemistry. In addition, 3 human gastric cancer cell lines were studied to determine the cellular localization of cdc25B by immunohistochemistry and cell fractionation followed by Western blotting. In the cell lines cdc25B was found to be present in both nuclei and cytoplasm, but predominantly in nuclei. High labeling indices of cdc25B in invasion front of gastric cancer was observed in 31 out of 125 cases (24.8%), linked to an advanced depth of cancer invasion (P=0.02), high rates of lymphatic invasion (P=0.03), and lymph node metastasis (P<0.01). Furthermore, the Kaplan-Meier method demonstrated a poor prognosis for cdc25B high labeling indices cases (P=0.02), although multivariate analysis revealed it not to be an independent factor. In conclusion, it seems likely that cdc25B is located predominantly in nuclei when overexpressed and this has some linkage with progression of gastric cancer.

Overexpression of phosphorylated histone H3 is an indicator of poor prognosis in gastric adenocarcinoma patients.

Ki-67 immunostaining is commonly used for assessing cell proliferation, but studies of its use as a prognostic indicator have revealed discordant results in gastric cancer patients. Recently, antibodies for phosphorylated histone H3 have been used to identify dividing cells because of its precise overexpression in mitosis. The authors tested the hypothesis that phosphorylated histone H3 overexpression might be a good prognostic indicator for gastric cancer patients by conducting an immunohistochemical comparison with Ki-67 in gastric cancer samples. One hundred twenty-two surgically resected primary cases were selected and histologically categorized in accordance with Lauren's classification. No correlation was found between phosphorylated histone H3 and Ki-67 regarding overexpression. However, correlations between phosphorylated histone H3 overexpression and clinicopathologic variables were noted for histologic type (intestinal type predominant in high labeling indices [LIs], defined as over the value of the 75th percentile; P<0.01), vessel invasion (positive in high LIs; P=0.05), and lymph node metastasis (positive in high LIs; P=0.04). With regard to Ki-67 overexpression, no correlation was evident with the clinicopathologic variables except histologic type (intestinal type predominant; P=0.05). By the Kaplan-Meier method with the log-rank test, cases overexpressing phosphorylated histone H3 showed a poorer prognosis than cases with low expression (P<0.01). In contrast, Ki-67 expression did not influence prognosis. Multivariate analyses indicated phosphorylated histone H3 overexpression to be an independent prognostic factor, together with lymphatic invasion and venous invasion (P<0.01). In conclusion, it seems likely that phosphorylated histone H3 plays an important role in the prognosis of gastric cancer, and its immunohistochemical investigation is useful for the prediction of prognosis in gastric cancer.