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Background Immune cells undergo extensive apoptosis in patients with cancer, which may be related to immune evasion by cancerous cells. The present study was designed to investigate the relationship between natural killer (NK) cell apoptosis and Fas expression in gastric cancer patients. Methods NK cell apoptosis and Fas expression were evaluated by multicolor flow cytometry. Soluble Fas ligand (sFasL) was quantitated by enzyme-linked immunosorbent assay. Results The frequency of apoptotic NK cells in gastric cancer patients was significantly higher than in normal controls (p = 0.0016). Moreover, their frequency was related to the progression of gastric cancer. Fas-positive NK cells were significantly more common in gastric cancer patients compared with normal controls (p = 0.034). Furthermore, Fas expression was closely related to the frequency of NK cell apoptosis (r = 0.6, p \ 0.0001). The frequency of tumor-infiltrating NK cell apoptosis was significantly higher than that of circulating NK cell apoptosis (p = 0.035). Furthermore, Fas-positive NK cells in gastric cancer tissues occurred significantly more often than in peripheral blood (p = 0.029). FasL concentration in gastric cancer patients was lower than that in normal controls, and the difference tended to be significant (p = 0.057). Apoptotic circulating NK cells significantly decreased after surgery compared to before surgery (p = 0.023). Furthermore, Fas expression on circulating NK cells also significantly decreased after surgery compared with before surgery (p = 0.021). Conclusions Upregulation of Fas expression on NK cells is related to increased apoptosis of circulating NK cells in gastric cancer patients.

Gastric cancer can be classified into three subgroups according to pattern of tumor infiltration into the surrounding tissue: INFa (expanding growth and a distinct border with the surrounding tissue), INFc (infiltrating growth and an indistinct border with the surrounding tissue), and INFb (in-between a and c). How the tumor infiltration pattern (INF) relates to prognosis and type of recurrence in advanced gastric cancer has not been sufficiently explored. We examined 805 consecutive advanced gastric adenocarcinoma patients who underwent curative gastrectomy at our institution between 1980 and 2005. Poor differentiation, serosal invasion, and lymph node metastasis were significantly more frequent in patients with INFc tumors than in those with INFa/b tumors. For patients with a T2 or T3 tumor, there was no significant difference in prognosis between those with INFa/b and with INFc. However, for patients with a T4a or T4b tumor, the prognosis of those with INFc was significantly worse than that of those with INFa/b. In multivariate analysis, INF was an independent prognostic indicator in T4a but not T2, T3, and T4b. Furthermore, the prognosis of T4 patients with INFc tumors was significantly worse than that of those with INFa/b, especially in node-negative but not in node-positive cases. In patients with a T4a or T4b tumor, peritoneal recurrence was significantly more frequent for those with INFc than for those with INFa/b. Our data indicate that INF is useful to predict the prognosis and recurrence pattern in T4a node-negative gastric cancer.

Proximal gastrectomy (PG) has been introduced for patients who are preoperatively diagnosed with early gastric cancer located in the upper third of the stomach. In the present study, we compared the prognosis of patients who underwent PG with that of patients who underwent total gastrectomy (TG). Between 1997 and 2006, 51 patients were diagnosed with early gastric cancer located in the upper third of the stomach and underwent PG. In the same period, 35 patients were diagnosed with early gastric cancer and underwent TG. Of these, in 24 patients, the cancer was localized in the middle to upper part of the stomach, and 11 patients had multiple cancers. We compared the clinicopathologic differences and prognoses between the two groups. Significantly fewer lymph nodes were dissected in the PG group (mean, 18.2) than in the TG group (mean, 36.6;P < 0.001). Complications were detected in 17.6% of patients in the PG group and in 14.3% of patients in the TG group, which was not significant (P = 0.678). The overall and disease-specific 5-year survival rates in the 51 patients who underwent PG (88.7% and 97.1%, respectively) were not different from those in the 35 patients who underwent TG (87.6% and 93.4%; P = 0.971 and P = 0.553; respectively). These findings indicate that PG can be performed safely and may have various advantages compared with TG in terms of patients' daily lives.

The combination of pre- and postoperative CRP was predictive of the prognosis of CRC patients.