Mechanisms of peritoneal metastasis after operation for non-serosa-invasive gastric carcinoma: an ultrarapid detection system for intraperitoneal free cancer cells and a prophylactic strategy for peritoneal metastasis.

PURPOSE: This aims of this study are to establish an ultra-rapid quantitative reverse transcription-PCR (RT-PCR) protocol that enables the diagnosis of i.p. cancer spread during operation, to reveal the mechanisms of peritoneal metastasis from non-serosa-invasive gastric carcinoma, and to evaluate the effect of the extensive intraoperative peritoneal lavage (EIPL) using the ultra-rapid quantitative RT-PCR as a prophylactic strategy for peritoneal metastasis. EXPERIMENTAL DESIGN: Peritoneal lavage samples from 63 patients with non-serosa-invasive gastric carcinoma were obtained at laparotomy and immediately after lymph node dissection. To identify the free cancer cells in the samples, carcinoembryonic antigen- and cytokeratin 20-specific RT-PCRs were performed using the LightCycler method in combination with an automated mRNA extractor. In addition, EIPL was performed in five cases with serosa-invasive gastric carcinoma, and its efficacy was evaluated by the ultra-rapid quantitative RT-PCR protocol. RESULTS: The method enabled us to complete the detection of cancer cells within approximately 70 min. Both the carcinoembryonic antigen and cytokeratin 20 mRNA in i.p. lavages after lymph node dissection were identified in three (14.3%), four (26.7%), and six (46.2%) patients with submucosal, muscularis propria, and subserosal tumors, respectively. Lymph node metastasis was the independent predictor of the existence of i.p. free cancer cells. The ultra-rapid quantitative RT-PCR demonstrated that EIPL reduced free cancer cells from 3.8 x 10(5) +/- 1.4 x 10(5) cells to 2.8 +/- 1.5 cells/100 ml lavage after six to eight washes, and they disappeared after seventh to ninth wash. CONCLUSIONS: The present study proved that lymph node dissection opened lymphatic channels and spread viable cancer cells into the peritoneal cavity. It is suggested that the combination of the novel detection system with the intraoperative therapy of EIPL can be a useful prophylactic strategy for peritoneal metastasis from gastric carcinoma.

Genetic pathways of 'de novo' colorectal carcinomas with reference to fetal-type glycogen phosphorylase positive foci.

'De novo' carcinogenesis has been advocated besides 'adenoma carcinoma sequence' as another dominant pathway leading to the colorectal carcinoma. Our previous study demonstrated that brain (fetal)-type glycogen phosphorylase (BGP) positive foci in the transitional mucosa (BGP foci) have frequent p53 mutations and that the distribution of BGP foci has a close relationship with the location of 'de novo' carcinoma. The aims of the present study were to investigate further genetic alterations in the BGP foci and to clarify the mechanism of 'de novo' carcinogenesis. Twenty-eight colorectal carcinomas with invasion into submucosa or superficial muscularis propria without any adenoma component expressing immunoreactive p53 protein were selected from 168 resected specimens. Investigations of the p53, K-ras and APC mutations was performed in the BGP foci, BGP negative colorectal mucosa and 'de novo' carcinoma using PCR-SSCP and DNA squencing. In all 28 cases, immunoreactive BGP was positive in the carcinomas and the BGP foci were observed sporadically in the mucosa adjacent to the carcinoma. No K-ras mutation was observed in either carcinoma or BGP foci in any of the cases. Mutations of p53 and APC were 14 (50.0%) and 9 (32.1%) in 'de novo' carcinomas, and 11 (39.3%) and 1 (3.6%) in BGP foci, respectively. Both p53 and APC mutations were detected in 8 and 1, p53 mutation alone in 6 and 10, APC mutation alone in 1 and 0 out of 28 carcinomas and BGP positive foci, respectively. These results suggest that the BGP foci may play a very important role in the 'de novo' colorectal carcinogenesis from the frequent genetic alterations of p53, and that there may be two major pathways, i.e., the p53-APC pathway and the p53 alone pathway, from the chain of genetic alterations between BGP foci and 'de novo' carcinoma.

BGP expression in gastric biopsies may predict the development of new lesions after local treatment for early gastric cancer.

BACKGROUND: Our previous studies have demonstrated the significant role of the generative cells of intestinal metaplasia (IM) expressing brain (fetal)-type glycogen phosphorylase (BGP) (BGP-IM) as a premalignant lesion of intestinal-type adenocarcinoma. The aims of the present study were to investigate the incidence of BGP-IM in gastric biopsy specimens and to establish BGP-IM as a predictor of the coexistence of accessory carcinoma and/or metachronous cancers before and after local treatment for early gastric carcinoma. METHODS: We studied the incidence of BGP-IM in eight endoscopic biopsy specimens of methylene blue-positive mucosa of the stomach obtained from patients with multiple gastric carcinomas (n = 14), a single carcinoma (n = 25), and atrophic gastritis (n = 20). RESULTS: BGP positivity was 93.3% in the multiple carcinomas and 80.0% in the single carcinomas. The incidences of BGP-IM (mean percentage +/- SD) in the stomachs with multiple carcinomas, single carcinoma, and atrophic gastritis were 83.2% +/- 22.8%, 36.5% +/- 41.3%, and 7.1% +/- 18.0%, respectively. The incidence was significantly higher in the stomachs with multiple carcinomas than in those with a single carcinoma or those with atrophic gastritis (P < 0.001). CONCLUSION: It is suggested that the frequent appearance of BGP-IM reflects the high potential of carcinogenesis of intestinal-type gastric cancer, and that the involvement of BGP-IM in more than 50% of the eight biopsies may be a predictor of the coexistence of accessory and/or metachronous carcinoma before and after local treatment for early gastric carcinoma.

Outpatient therapy with irinotecan and low-dose cisplatin for metastatic colorectal cancer resistant to 5-fluorouracil.

Chemotherapy with irinotecan hydrochloride and low-dose cisplatin was tested for the treatment of metastatic colorectal cancer showing resistance to 5-fluorouracil. Eleven consecutive patients with advanced metastatic colorectal cancer (performance status: 0 to 2), who had shown tumor progression on chemotherapy with 5-fluorouracil/leucovorin, were treated with irinotecan (60 mg/m2) plus cisplatin (6 mg/m2) by 90-min intravenous infusion. Treatment was repeated weekly for 3 weeks during admission and then fortnightly on an outpatient basis. Objective responses were observed in four patients (36%; 95% confidence interval: 11%-69%). The median duration of response was 5.5 months and six patients are still alive. The time to disease progression was longer in the no change group (7.0+/-3.6 months: mean +/- SD) than in the responder group (5.5+/-1.9 months), and there was no difference of median survival between the two groups (10.0 versus 10.3 months). The overall median survival was 8.2 months (range: 4 to 12+ months). This treatment was well tolerated. Six patients experienced grade 1 or 2 leucopenia, while grade I diarrhea and nausea occurred in three and five patients, respectively. Based on the good response, excellent quality of life, and convenience, the present regimen seems to be reasonable second-line outpatient chemotherapy for patients with metastatic colorectal cancer showing resistance to 5-fluorouracil.