Shigeru Tatebe

Serum interleukin-6 and -10 levels in patients with gastric cancer

BackgroundInterleukin-6 (IL-6) is known to be a multifunctional cytokine and IL-10 is an immunosuppressive factor. Both have been reported to be related to the disease prognosis in some human solid tumors. In the present study, we evaluated the clinical significance of preoperative serum IL-6 and IL-10 levels as new tumor markers in patients with gastric cancer (GC).MethodsPreoperative serum samples from 90 patients with GC and 9 normal healthy volunteers were assayed. Levels of IL-6 and IL-10 were determined by enzyme-linked immunosorbent assay (ELISA). The clinical significance of serum IL-6 and IL-10 levels was evaluated and compared with serum carcinoembryonic antigen (CEA) levels and serum C-reactive protein (CRP) levels in these patients.ResultsThe serum level of IL-6 was significantly higher in the GC patients than in the healthy subjects. Serum IL-6 levels were strongly correlated with CRP levels, but did not correlate with CEA or carbohydrate antigen (CA) 19-9 levels. Serum IL-10 levels did not correlate with CEA, CA19-9, or CRP. Strong positive correlations between serum IL-6 levels and tumor size and tumor stage were observed. On the other hand, IL-10 did not correlate with such clinicopathological findings of tumors. However, high serum IL-10 levels were associated with a worse prognosis in the GC patients, independently of their tumor stage.ConclusionThese findings indicate that serum IL-6 may suggest gastric cancer progression. On the other hand, IL-10 may play an important role in host immunity and the prognosis of GC patients.

Apoptosis occurs more frequently in metastatic foci than in primary lesions of human colorectal carcinomas: analysis by terminal-deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labeling.

We examined the occurrence of apoptotic cell death in 15 advanced colorectal carcinomas with lymph‐node and/or liver metastases by terminal‐deoxynucleotidyl‐transferase (TdT)‐mediated dUTP‐biotin nick end labeling (TUNEL). TUNEL‐positive cells were used to quantify the apoptotic index (AI: percentage of TUNEL‐positive cells in carcinomatous cells). Similarly, Ki‐67‐positive cells were used to quantify Ki‐67 labeling (Kl: percentage of Ki‐67‐positive cells in carcinomatous cells) as a proliferative index. The mean AIs of primary colorectal carcinomas, lymph‐node and liver metastases were 3.5%, 5.6% and 6.2% respectively. There was a significant group difference between primary carcinomas and lymph‐node or liver metastases. The mean Kls of primary colorectal carcinomas, lymph‐node and liver metastases were 51.8%, 60.1% and 61.7% respectively. There was a significant group difference between primary carcinomas and lymph‐node or liver metastases. In addition, there was a close positive relationship between the AI and MI per specimen. There was no apparent correlation between AI or MI and the expression of nuclear p53 of cancer cells. These results suggested that cell proliferation and loss (apoptosis) were more frequent in metastatic foci than in primary lesions, and that apoptosis might reflect not only cell loss but also the proliferative activity of human colorectal carcinomas.

Apoptosis in human gastric mucosa, chronic gastritis, dysplasia and carcinoma: analysis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling

We examined the existence and distribution of apoptotic cells in human gastric mucosa, chronic gastritis, adenomatous dysplasias and carcinomas in 15 surgically removed stomachs in which dysplasia and carcinoma were found simultaneously. Serial sections were cut for immunohistochemistry for p53 oncoprotein and Ki-67 antigen, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL). TUNEL signal-positive apoptotic cells were rare in normal mucosa, while a few apoptotic cells were noted in gastritic mucosa and intestinal metaplasia, intermingled with Ki-67 antigen-positive cells forming a generative cell zone. This suggests the cell-cycle-dependent apoptosis of gastric mucosa. The frequency of apoptotic cells per crypt was higher in incomplete than in complete metaplasia, implying greater underlying DNA damage in the former. TUNEL indices (TI; percentage of TUNEL-positive cells in tumour cells) were slightly higher in adenomatous dysplasias (4.9±2.1) than in carcinoma (3.9±1.1), but there was no no statistical difference. Ki-67 indices (KI; percentage of Ki-67 antigen-positive cells in tumour cells) were significantly (P<0.05) higher in carcinomas than in dysplasias. Thus, gastric adenomatous dysplasias were characterized by relatively higher TI and lower KI, which might reflect a more static growth potential. The expression of p53 oncoprotein in cancer cells is thought to be an apoptosis-suppressing event, although its precise role remains to be elucidated. Overall, these results indicate that apoptosis plays a crucial part in the morphogenesis of gastritic mucosa including intestinal metaplasia, and that the process is correlated both with tumourigenesis and with proliferative activity.

Distinct recurrence pattern and outcome of adenocarcinoma of the gastric cardia in comparison with carcinoma of other regions of the stomach

BackgroundCarcinoma arising in the cardioesophageal junction is a distinct clinical entity compared with tumors located in other regions of the stomach. The prognosis for adenocarcinoma of the upper stomach is considered to be relatively poorer than carcinomas of the more distal stomach. We have therefore investigated patients with carcinoma of the gastric cardia in order to evaluate the underlying cause of this poor prognosis.Materials and MethodsClinicopathologic features and postoperative prognosis of 101 patients with carcinoma of the cardia were evaluated and compared with findings on 1884 patients with tumors in other regions of the stomach.ResultsTumors of the cardia had a mean size of 6.8 cm, which was significantly larger than the mean size of 5.9 cm for tumors found in the middle- and lower third of the stomach. The incidence of serosal invasion, lymph node metastasis, and lymphatic and blood vessel invasion was higher in association with adenocarcinoma of the cardia than with adenocarcinoma in remaining parts of the stomach. In the analysis of patients who had undergone curative resection, the 5-year survival rates were 61.6, 79.1, and 82.6% in patients with carcinoma of the cardia, upper one-third, and remaining middle- and lower one-third of the stomach, respectively, and the differences were statistically significant. Multivariate analysis indicated that adenocarcinoma of the gastric cardia is an independent prognostic factor. With regard to the site of recurrence, both lymph node and hematogenous recurrence were observed more frequently in the cardia than in the remaining parts of the stomach.ConclusionsOur data indicate that the prognosis of patients with adenocarcinoma of the gastric cardia is extremely poor. To improve their prognosis, new treatments in addition to gastrectomy with extensive lymph node dissection are needed.

Expression of polo-like kinase 1 (PLK1) protein predicts the survival of patients with gastric carcinoma.

Objective: To assess the prognostic value of polo-like kinase 1 (PLK1), an important regulator of cell cycle progression, in patients with gastric carcinoma. Methods: PLK1 expression was determined in 160 gastric carcinoma patients by immunohistochemistry and compared with p53 expression and the proliferating cell nuclear antigen-labeling index (PCNA-LI) to evaluate the effect of PLK1 on tumor progression. Furthermore, PLK mRNA expression was determined in 26 advanced gastric cancer patients by reverse transcription-polymerase chain reaction (RT-PCR). Results: PLK mRNA expression was detected in 25 (96.2%) patients by RT-PCR. Immunohistochemical staining revealed PLK1 expression in 84 (52.5%) patients. There were no significant relationships between PLK1 expression and various clinicopathological factors. PLK1 expression was significantly correlated with the PCNA-LI, but not p53 expression. The prognosis of patients with PLK1-positive tumors was significantly worse than that of patients with PLK1-negative tumors (p < 0.05). Moreover, multivariate analysis revealed that PLK1 expression was an independent prognostic factor. Patients with PLK1-positive and high PCNA-LI tumors showed a significantly poorer prognosis than patients with PLK1-negative and/or low PCNA-LI tumors. Furthermore, the prognosis of patients with PLK1- and p53-positive tumors was significantly worse than that of patients with PLK1- and p53-negative or PLK1-negative and p53-positive tumors. Conclusion: PLK1 expression may be a critical indicator of a poor prognosis in patients with gastric carcinoma.

Expression of Fas antigen and its mediation of apoptosis in human gastric cancer cell lines

Fas, a member of the tumor necrosis factor receptor/nerve growth factor receptor family, induces apoptosis by crosslinking with Fas ligand or anti‐Fas antibody in a variety of cultured cells. We examined the expression of Fas antigen and its mediation of apoptosis in six human gastric carcinoma cell lines. Flow cytometric analysis and western blotting revealed relatively high expression of Fas antigen in MKN‐74 (wild‐type p53 gene) and MKN‐45 (wild‐type), followed by MKN‐1 (mutated), MKN‐7 (mutated) and KATO‐III (deleted). MKN‐28 (mutated) showed minimal expression of the antigen. The expression was apparently enhanced by interferon‐γ, except for MKN‐1 and MKN‐28. Anti‐Fas antibody (100 ng/ml) induced nuclear fragmentation characteristic of apoptosis. Apoptosis occurred in a delayed fashion and the apoptotic index at 72 h was approximately 60% in MKN‐74, 35% in MKN‐45, and 20% in MKN‐1 and KATO‐III. A DNA ladder was noted in MKN‐74 at 72 h. Expression levels of P53 and P21Wafl did not change for up to 48 h in MKN‐74. The biological effects did not correlate with endogenous Bcl‐2 expression. These results indicated that a) Fas antigen is variably expressed in human cultured gastric carcinoma cells, b) the protein transduces an apoptotic signal which leads to delayed cell death, and c) susceptibility to the antibody correlates well with the expression level of Fas antigen.

EFFECT OF AGE ON PROGNOSIS IN PATIENTS WITH GASTRIC CANCER

Background:  The incidence of gastric cancer among the elderly has recently been increasing; however, the prognostic value of age in patients with gastric cancer remains elusive.

Decreased NKG2D Expression on CD8+ T Cell Is Involved in Immune Evasion in Patients with Gastric Cancer

Purpose: Some studies suggest that the immunoreceptor NKG2D expression on CD8+ T cells is down-regulated and this reduction may be involved in immune evasion in cancer patients. The present study was designed to investigate NKG2D expression on CD8+ T lymphocytes and its relationship to immune evasion in gastric cancer patients. Experimental Design: NKG2D expression on both circulating and tumor-infiltrating CD8+ T cells was evaluated by multicolor flow cytometry. Soluble MHC class I chain-related gene A (MICA) in the sera was quantitated by ELISA. Transwell experiments were carried out to determine the effect of cancer cells on NKG2D expression. Results: NKG2D expression on circulating CD8+ T cells was down-regulated and significantly correlated with IFN-γ production in gastric cancer patients (r = 0.68; P = 0.007). NKG2D expression was closely related to undifferentiated cancer (P = 0.021) as was the depth of invasion (P = 0.012). There was no difference in soluble MICA between gastric cancer patients and normal controls. NKG2D expression on CD8+ T cells was remarkably reduced in the tissue of gastric cancer compared with peripheral blood (P = 0.046). Complete removal of tumor by surgery restored NKG2D expression on CD8+ T cells (P = 0.0049). Transwell experiments showed that this down-regulation was induced by direct contact between cancer cells and CD8+ T cells and that soluble factors did not affect the NKG2D expression. This phenomenon was blocked by the addition of anti-MICA antibodies. Conclusions: Decreased NKG2D expression may be one of the key mechanisms responsible for immune evasion by tumors in gastric cancer.

5-Fluorouracil (5-FU) induced apoptosis in gastric cancer cell lines: role of the p53 gene

We examined chemosensitivity to 5-fluorouracil (5-FU) in four human gastric cancer cell lines, by analyzing the expression of p53 and its related genes. Treatment with 1mM 5-FU induced variable degrees of apoptosis in the cultured cells. The apoptotic indices 72 h after treatment were approximately 14% in MKN-74 (wild-type p53 gene), 12% in MKN-45 (wild-type), 3% in MKN-28 (mutated) and 0.5% in KATO-III cells (deleted), respectively. On the other hand, 50 μM 5-FU had little effect on the induction of apoptosis in MKN-74 cells, the value being approximately 2% after 72 h. Induction of P53 expression was noted 3 h after initiating the treatment, followed by the induction of P21/Waf1 after 6 h in both MKN-74 and MKN-45 cells. The same expression mode was noted in MKN-74 treated with 50 μM 5-FU. Conversely, the level of P53 expression was constant in MKN-28 cells and absent in KATO-III cells, in which P21/Waf1 had never been induced. The Bax/Bcl-2 expression ratio was gradually elevated for up to 72 h in MKN-74 and MKN-45 cells treated with 1mM 5-FU; in contrast, it was unchanged in MKN-28 and KATO-III cells, and MKN-74 treated with 50 μM 5-FU. These results might indicate that (1) 1mM 5-FU induces apoptosis in cultured gastric cancer cells carrying the wild-type p53 gene, but not those carrying the mutated type or a gene deletion, and (2) the elevated Bax/Bcl-2 expression ratio plays a more crucial role than the higher expression of P21/Waf1 in the induction of p53- gene dependent apoptosis.

Prognostic indicators in node-negative advanced gastric cancer patients.

Despite carrying better overall prognoses, some node‐negative gastric cancer patients die from recurrent malignancies. Identifying factors associated with disease‐specific survival in adequately staged node‐negative gastric cancer is important, as these patients are presumably free of microscopic regional metastases and may derive significant benefit from existing or future adjuvant strategies.