Shinichi Oka

Less invasive surgery for early gastric cancer based on the low probability of lymph node metastasis

BACKGROUND Less invasive treatment is the current trend in many surgical fields. Most patients with early gastric cancer do not have lymph node metastasis. Thus extensive resection of the stomach and extended lymph node dissection do not appear to be necessary. METHODS In a retrospective study, 890 consecutive patients with early gastric cancer who had undergone standard gastrectomy were assessed for depth of invasion, gross appearance, and maximum diameter of the tumor to examine the possibility of limiting the extent of lymph node dissection. A variety of limited gastrectomies have been developed and now include endoscopic mucosal resection, wedge resection, segmental gastrectomy, limited proximal gastrectomy, and distal hemigastrectomy. RESULTS A retrospective study revealed that extensive lymph node dissection did not improve the survival of patients with early gastric cancer. Endoscopic mucosal resection was suitable for cancers of the depressed type of less than 1 cm in diameter and the elevated type of less than 2 cm in diameter. Wedge, segmental, or limited proximal gastrectomy was suitable for the elevated type of 2 to 3 cm in diameter. The elevated type of more than 3 cm in diameter and the depressed type of 1 to 3 cm in diameter sometimes involved metastasis to group 1 nodes. The depressed type of more than 3 cm in diameter sometimes involved metastasis to group 2 nodes. Thus such cases should be treated by gastrectomy with dissection of potentially metastatic lymph nodes. CONCLUSIONS Limitation of the extent of gastrectomy and lymph node dissection may be possible, depending on the gross appearance and size of the tumor.

The expression of transforming growth factor-β1 is significantly correlated with the expression of vascular endothelial growth factor and poor prognosis of patients with advanced gastric carcinoma

Transforming growth factors β (TGFs β) are involved in a variety of important cellular functions, including cell growth and differentiation, adhesion, migration, extracellular matrix formation, and immune function. Moreover, it has been reported that TGFs β are correlated with angiogenesis. However, the role of TGF‐β as an angiogenic factor in gastric carcinoma is still unclear.

The expression of thymidine phosphorylase correlates with angiogenesis and the efficacy of chemotherapy using fluorouracil derivatives in advanced gastric carcinoma

SummaryThe expression of thymidine phosphorylase (TP) and the density of microvessel in advanced gastric carcinoma were examined by immunohistochemistry to evaluate the significance of TP. The expression of TP was negative in 72 cases, positive in 54. The microvessel density correlated with the expression of TP. In total cases, patients with TP-positive tumours survived longer than those with TP-negative tumours. In patients treated with fluorouracil derivatives (FUs), the expression of TP significantly correlated with favourable prognosis and with unfavourable prognosis in those not treated with FUs. The patients with TP-positive tumours, the prognosis of patients treated with FUs was significantly better than that of those not treated with FUs. In patients with TP-positive tumours, treatment with FUs and lymph node metastasis were independent prognostic factors according to the Cox proportional hazards model. Depth of invasion and lymph node metastasis were independent prognostic factors in patients with TP-negative tumours. The determination of the expression of TP might be useful for predicting the efficacy of post-operative chemotherapy using FUs to prevent recurrence in advanced gastric carcinoma patients who undergo curative gastrectomy.

The expression of murine double minute 2 is a favorable prognostic marker in esophageal squamous cell carcinoma without p53 protein accumulation

BackgroundMurie double minute 2 (MDM2) is an oncoprotein that inhibits the function of p53 tumor-suppressor protein. Although there have been a few reports onMDM2 gene abnormalities, there has been no investigation into expression of the product of this gene in esophageal squamous cell carcinoma. Thus, the clinicopathological and prognostic significance of the product of theMDM2 gene is as yet unknown.MethodsMDM2 protein expression status was analyzed in surgically resected materials by immunohistochemical procedures.ResultsThe expression of MDM2 significantly correlated inversely with tumor size, depth of invasion, lymph node metastasis, lymphatic vessel invasion, and stage of disease. However, the expression of MDM2 correlated with neither p53 protein accumulation status nor Ki-67 labeling index. The prognosis with MDM2-positive status was significantly better than that with MDM2-negative status for patients with p53-negative tumors, but not in those with p53-positive tumors. Moreover, multivariate analysis showed that the expression of MDM2 was an independent prognostic factor in patients with p53-negative tumors.ConclusionsThese findings indicate that MDM2 immunohistochemical analysis may provide useful information concerning the prognosis in esophageal squamous cell carcinoma patients with p53-negative tumors.

Combined analysis of p53 and retinoblastoma protein expressions in esophageal cancer.

BACKGROUND p53 gene mutation and abnormal p53 protein expression, also loss of the retinoblastoma gene and protein expression are frequently associated with esophageal squamous cell carcinoma (ESCC). Recently, the prognostic significance of the combined analysis of p53 protein and retinoblastoma protein (pRB) has been reported in non-small cell lung cancer. However, in ESCC, the prognostic significance of the combined analysis of these proteins remains unclear. In this study, we immunohistochemically analyzed the p53 protein and pRB expressions in surgically resected ESCC, and we evaluated the prognostic significance of the combination of these proteins. METHODS We analyzed p53 protein and pRB expressions immunohistochemically in 191 surgically resected ESCC cases. Overexpression of p53 and loss of pRB were considered abnormal. RESULTS Overexpression of p53 protein was detected in 79 patients (41%) and decreased pRB nuclear staining occurred in 82 (43%). The Kaplan-Meier survival curve showed that absence of pRB expression was significantly associated with shortened survival (p = 0.001), whereas expression of p53 was not significantly associated with survival. Moreover, p53 and pRB status individually were not independent prognostic factors in multivariate survival analysis. With respect to pRB and p53, the tumors could be grouped into four categories: p53-/pRB+ (31%); p53-/pRB- (27%); p53+/pRB+ (26%); and p53+/pRB- (16%). Favorable prognosis was observed in patients with p53-/pRB+ tumors. Multivariate analysis showed p53-/pRB+ status to be an independent prognostic factor. CONCLUSIONS The combination of p53 protein loss and pRB expression was associated with good prognosis in patients with ESCC.

Computerized nuclear morphometry: a new morphologic assessment for advanced gastric adenocarcinoma.

OBJECTIVE To evaluate the correlation between the morphologic nuclear features and clinicopathologic parameters in patients with advanced gastric cancer. SUMMARY BACKGROUND DATA Nuclear profiles have been reported as useful prognostic predictors in various cancers. Data from computerized morphometries are objective and quickly derived using conventional microscopic analysis. However, this image analysis of nuclear features has rarely been applied to investigations of gastric adenocarcinoma. Moreover, it remains to be shown what types of biologic factors influence the nuclear features. METHODS Morphometric nuclear features (nuclear area, perimeter, and shape) were analyzed in 202 patients with serosal-invaded gastric cancer (stage II and III) who underwent curative gastrectomy. In each case, 300 cancer nuclei were analyzed on routine hematoxylin and eosin-stained slides through the use of a computer-assisted image analysis system by tracing the nuclear profiles (magnification x400) on a computer monitor. The morphometric data were compared with patient survival, clinicopathologic status, DNA ploidy pattern of tumors, expression of p53 protein, and proliferative activity of cancer cells. RESULTS Lymph node metastasis, lymphatic invasion, and venous invasion were more frequently detected in patients with large nuclear areas. Significant correlations were detected between the size of the nuclear area of cancer cells and the biologic factors of tumors, such as expression of p53, Ki-67 labeling index, and DNA ploidy pattern. The 5-year survival rate of the 100 patients in the large-nuclear group (nuclear area >45.3 microm2) was 47.6% and was significantly lower than the 74.4% rate of the 98 patients in the small-nuclear group (nuclear area < or =45.3 microm2). Moreover, the nuclear area was found to be an independent prognostic factor in the multivariate analysis. CONCLUSIONS Gastric cancer cells with a large nuclear area express mutated p53 protein and have high proliferative activity. Moreover, such cancer cells have high potential for invasion to the microvessels in the gastric wall. Thus, nuclear morphometry is a new and useful morphologic predictor for metastatic potential in advanced gastric cancer.

Administration in a Hypotonic Solution Is Preferable to Dose Escalation in Intraperitoneal Cisplatin Chemotherapy for Peritoneal Carcinomatosis in Rats

An animal model of intraperitoneal (i.p.) cisplatin chemotherapy using hypotonic solutions of sodium chloride has been developed as a treatment for peritoneal carcinomatosis. The concentrations of platinum in the plasma and in the i.p. fluid of Donryu rats were measured after i.p. injection of hypotonic (103 or 154 mosm/l) and isotonic (308 mosm/l) solutions that contained an equal amount of cisplatin. The maximum concentration (Cmax) and the area under the curve of concentration versus time (AUC) of platinum in the plasma increased proportionately with increases in the dose of cisplatin and they were significantly higher in rats given cisplatin in hypotonic solutions than in those given the drug in isotonic solution. The Cmax and AUC of total platinum were similar for the solution of 103 mosm/l with 2.5 mg/kg cisplatin and the isotonic solution with 5.0 mg/kg cisplatin. The Cmax and AUC of free platinum in the plasma did not increase with increases in the dose of cisplatin in isotonic solution but did increase after hypotonic injection. However, the solutions of lower osmolarity gave a decreased AUC of platinum in the i.p. fluid. Hypotonic conditions continued for 30 min at most after i.p. injection of hypotonic solutions. When the same dose of cisplatin was given to rats with tumors derived from AH100B carcinoma cells, the amount of platinum taken by i.p. solid tumors from the solution of 103 mosm/l was about twice that from the isotonic solution and was much the same as that taken up from the isotonic solution with twice the amount of cisplatin. These results indicate that hypotonic i.p. cisplatin chemotherapy might be preferable to escalation of the dose of i.p. cisplatin in the treatment of peritoneal carcinomatosis.

Prognostic significance of RCAS1 expression in relation to the infiltration of dendritic cells and lymphocytes in patients with esophageal carcinoma.

RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) expression was determined in 107 esophageal carcinoma patients by immunohistochemical procedures and compared with tumor infiltrating lymphocyte (TIL) and dendritic cell (DC) infiltration to evaluate the effect of RCAS1 on immune responses in esophageal carcinoma. RCAS1 immunoreactivity was detected in 59 of 107 patients (55.1%). RCAS1 expression was significantly correlated with the depth of invasion, lymph node metastasis, and histologic stage. RCAS1 expression tended to be correlated with a lower TIL density in tumors with marked DC infiltration. The survival time for patients with RCAS1-negative tumors was significantly longer than that for patients with RCAS1-positive tumors. Especially, the prognosis was predicted by RCAS1 in cases with marked DC infiltration. Multivariate analysis revealed that RCAS1 expression was an independent prognostic factor. RCAS1 expression may play an important role in evading the immunological defense mechanisms in esophageal carcinoma.

Clinicopathological significance of cathepsin D expression in gastric adenocarcinoma.

Objective: An estrogen-regulated lysosomal protease, cathepsin D, has been detected in a variety of tissues. This proteinase has been described as closely associated with tumor progression and metastasis in malignant tumors. The purpose of this study was to determine the clinicopathological and prognostic significance of cathepsin D expression in gastric adenocarcinoma. Methods: In a consecutive series of 478 patients with gastric carcinoma (median follow-up period: 93 months, range: 1–285 months), cathepsin D expression in tumors was quantitatively analyzed with immunohistochemistry using a monoclonal antibody against cathepsin D (clone: 1C11). The percentage of cathepsin-D-positive cancer cells (the CD index) was calculated. In addition, the amount of cathepsin-D-positive stromal cells was evaluated; three grades (high, intermediate, and low) were used for the classification. Results: The mean CD index of 478 tumors was 12.8% (range: 0–100%, median: 8%). The mean CD index of diffuse-type gastric carcinomas (14.9%) was significantly higher than that of intestinal-type carcinomas (10.1%, p < 0.0001). Cathepsin D expression of cancer cells was significantly associated with the depth of tumor invasion in both types. The percentage of tumors with high cathepsin D expression in stromal cells was significantly higher in well-differentiated tumors (25.5%) than in moderately differentiated (12.8%) or in poorly differentiated tumors (19.1%). Cathepsin D expression of stromal cells was significantly associated with the depth of tumor invasion in the intestinal type, in contrast to the diffuse type. Highly expressed cathepsin D in cancer cells was associated with a poor prognosis in both types of carcinoma, but in stromal cells highly expressed cathepsin D was associated to a poor prognosis in the intestinal type only. Conclusion: These results indicate that cathepsin D expression in cancer cells may play an important role in tumor progression in diffuse-type gastric carcinoma, whereas in the intestinal type of carcinoma, cathepsin D expression in stromal cells may play an important role in tumor progression.

The expression of vascular endothelial growth factor and proliferative activity of cancer cells in gastric cancer

Background/aims: Vascular endothelial growth factor (VEGF) is one of the most important factors for angiogenesis in various malignant tumors. However, the clinicopathological and biological significance of the expression of VEGF in gastric cancer remains unclear. In this study, we investigated the relationship between the expression of VEGF and the clinicopathological and biological status of advanced gastric cancer, all of the same stage. Patients/methods: The expression of VEGF was immunohistochemically examined using the polyclonal antibody A-20 in tumors from 97 patients with invasion of the serosa but no lymph-node metastasis (t3, n0, stage II). The results were compared with clinicopathological and biological status (microvessel density and proliferative activity) of tumors. Results: Expression of VEGF was detected in 27 of 97 tumors (28%). The mean microvessel density (MVD) of 27 VEGF-positive tumors (458/mm2) was higher than that of 70 VEGF-negative tumors (331/mm2, P=0.0001). However, the proliferative activity expressed as the Ki-67 labeling index (LI; percentage of immunostained cancer cells) of 27 VEGF-positive tumors (13.8%) was significantly lower than that of 70 VEGF-negative tumors (26.7%, P=0.0002). In 48 tumors with low proliferative activity of cancer cells (Ki-67 LI≤18%), 20 (42%) tumors expressed VEGF, and these tumors had a high MVD (4461/mm2). In the 93 surviving patients, the 5-year survival rate of the 25 patients with VEGF-positive tumors (64%) was not different from that of the 68 patients with VEGF-negative tumors (73%, P=0.4296). Conclusion: Advanced gastric carcinoma with low proliferative activity may produce VEGF and may have high angiogenic potential in order for the tumor itself to grow. However, the prognosis of patients with such tumors was not unfavorable.