Prediction of sensitivity of rectal cancer cells in response to preoperative radiotherapy by DNA microarray analysis of gene expression profiles.

Preoperative radiotherapy has been widely used to improve local control of disease and to improve survival in the treatment of rectal cancer. However, the response to radiotherapy differs among individual tumors. Our objective here was to identify a set of discriminating genes that can be used for characterization and prediction of response to radiotherapy in rectal cancer. Fifty-two rectal cancer patients who underwent preoperative radiotherapy were studied. Biopsy specimens were obtained from rectal cancer before preoperative radiotherapy. Response to radiotherapy was determined by histopathologic examination of surgically resected specimens and classified as responders or nonresponders. By determining gene expression profiles using human U95Av2 Gene Chip, we identified 33 novel discriminating genes of which the expression differed significantly between responders and nonresponders. Using this gene set, we were able to establish a new model to predict response to radiotherapy in rectal cancer with an accuracy of 82.4%. The list of discriminating genes included growth factor, apoptosis, cell proliferation, signal transduction, or cell adhesion-related genes. Among 33 discriminating genes, apoptosis inducers (lumican, thrombospondin 2, and galectin-1) showed higher expression in responders whereas apoptosis inhibitors (cyclophilin 40 and glutathione peroxidase) showed higher expression in nonresponders. The present study suggested the possibility that gene expression profiling may be useful in predicting response to radiotherapy to establish an individualized tailored therapy for rectal cancer. Global expression profiles of responders and nonresponders may provide insights into the development of novel therapeutic targets.

Using the supercharge technique to additionally revascularize the gastric tube after a subtotal esophagectomy for esophageal cancer.

BACKGROUND: Maintaining sufficient blood flow to the gastric tube after a subtotal esophagectomy for esophageal cancer is crucial for decreasing esophagogastric anastomotic leakage. METHODS: After subtotal esophagectomy for esophageal cancer, the supercharge technique was performed in 21 esophageal reconstruction patients to additionally revascularize the gastric tube using the splenic artery and vein, external carotid artery, and internal jugular vein. Operative results of the supercharge group were retrospectively compared with those of the control group (patients not receiving the technique). RESULTS: Both operation time and operative blood loss in the supercharge group were significantly longer and larger than those of the control group. However, the incidence of anastomotic leakage was significantly lower in the supercharge group than in the control group. CONCLUSION: This practical supercharge technique reduces leakage during esophageal anastomosis.

Expression pattern of telomerase reverse transcriptase in rectal carcinoma predicts tumor radiosensitivity, local recurrence and disease-free survival.

BACKGROUND/AIMS: Predictive indicators of radiosensitivity in rectal cancer are required in order to avoid unnecessary preoperative radiotherapy. Telomeres are specialized structures at the ends of chromosomes that protect against that such as irradiation. Lower telomerase activity has been reported to be related to radiosensitivity in vitro or vivo. The aim of this study was to examine the possible role of telomerase reverse transcriptase expression, which is correlated to telomerase activity, in determining tumor radiosensitivity, local recurrence, and disease-free survival in patients with rectal carcinomas. METHODOLOGY: We studied 96 cases with advanced rectal carcinoma. In preradiation biopsy specimens of tumor samples, the number of cells stained positive for telomerase reverse transcriptase protein was evaluated by immunohistochemistry. RESULTS: The expression pattern of telomerase reverse transcriptase protein correlated with tumor radiosensitivity (P=0.0007). All tumors that had a high percentage of telomerase reverse transcriptase positive cells were radioresistant. High telomerase reverse transcriptase expression pattern is a predictive marker for high local recurrence or poor survival in patients with rectal cancer (P=0.011, P=0.0005). Telomerase reverse transcriptase expression and histopathological grade were significant prognostic variables for disease-free survival in the multivariate analysis (P=0.0003, P=0.0091). CONCLUSIONS: Telomerase reverse transcriptase raises the predictive possibility of tumor radiosensitivity in rectal cancer. Telomerase reverse transcriptase might be a useful parameter for patient selection for preoperative radiotherapy in rectal carcinoma.

Prognostic significance of Ku70 protein expression in patients with advanced colorectal cancer.

BACKGROUND/AIMS: Ku protein stimulates DNA repair and signals the damage/stress responses, which may affect apoptosis and cell proliferation. The expression of Ku70 has been reported to be related to cell proliferation in a human gastric cancer cell line. However, in colorectal carcinoma, the clinical significance of Ku70 expression remains unclear. We examined the expression pattern of Ku70 in sporadic colorectal cancer and its relation to clinicopathological parameters and survival. METHODOLOGY: We studied 101 consecutive cases of advanced colorectal carcinoma. In resected specimens, the number of cells stained positive for Ku70 protein was evaluated by immunohistochemistry. RESULTS: The percentage of cells expressing Ku70 in different tumors ranged from 4.2-99.7%. The elevated Ku70 expression group comprised 52 of 101 cases (52%). No significant correlation was seen between Ku expression pattern and the clinical parameters except depth of invasion. pTNM stage, histopathological grade and Ku70 were significant variables for prognosis of survival in the multivariate analysis. CONCLUSIONS: This is the first report correlating reduced survival with elevated expression of Ku protein in colorectal adenocarcinoma. Ku may be a new prognostic marker useful for selecting adjuvant treatment strategies.

Evaluating the combination of molecular prognostic factors in tumor radiosensitivity in rectal cancer.

BACKGROUND/AIMS: The local recurrence ratio following surgery alone is higher in patients with rectal cancer than in those with colon cancer. Preoperative radiotherapy reduces the rate of local recurrence and improves the chances of survival in patients with resectable advanced rectal carcinoma. Identification of predictive indicators of radiosensitivity is useful in selecting patients best suited for preoperative radiotherapy and thus helps to avoid unnecessary preoperative treatment. We investigated whether the combination of Ku, p53, p21, and p16 predicted tumor radiosensitivity. METHODOLOGY: We studied 96 cases with advanced rectal carcinoma. In preradiation biopsy specimens of tumor samples, all immunoreactive nuclei of cells stained positive for Ku, p53, p21, and p16 were evaluated by immunohistochemistry. The expression of p53, p21 and p16 in more than 5% of tumor cells were defined as positive, whereas both Ku70 and Ku86 protein in more than 70% of such cells were defined as Ku positive. The expression patterns of Ku, p53, p21, and p16 were examined for association with tumor radiosensitivity, which was determined according to the criteria of histopathologic assessment of radiotherapy effects. RESULTS: Univariate analysis showed a correlation between the expression patterns of Ku, p53, p21, and p16 and tumor radiosensitivity, while multivariate analysis showed that the expression pattern of Ku and p16 significantly correlated with tumor radiosensitivity. The combination of Ku and p16, or Ku, p53, p21 and p16 was therefore a good predictive marker for tumor radiosensitivity. CONCLUSIONS: These findings tend to support the hypothesis that the combination of Ku, p53, p21, and p16 expression after radiotherapy can act as a marker for radiosensitivity. Further investigation is needed, as the number of cases in this study was limited.

What types of colorectal cancer overexpress the MAGE protein?

BACKGROUND/AIMS: Tumor-specific antigens such as Melanoma-associated antigens could be attractive targets for immunotherapy. It will be a great help for cancer immunotherapy to distinguish what types of tumor expresses tumor-specific antigen. METHODOLOGY: We investigated the expression pattern of MAGE-A1 by immunohistochemical typing methods in human colorectal cancers obtained from consecutive patients undergoing surgical treatment at the hospital of the University of Tokyo. RESULTS: In 35 of 89 cases (39%), MAGE-A1 positive immunoreactivity was detected in the malignant glands. MAGE-A1 positive immunoreactivity was significantly higher among the patients under the age of 70 than among those 70 years of age and older (p=0.04). Among the patients under the age of 70, the tumors located in the distal colon (descending colon, sigmoid colon and rectum) showed significantly more positive MAGE-A1 immunoreactivity than those in the proximal colon (cecum, ascending colon and transverse colon) (p=0.04). The expression pattern of MAGE-A1 was not associated with gender, size, depth, histological type, vessel invasion, lymphatic invasion, lymph nodal invasion or stage of disease. CONCLUSIONS: Relatively better results can be expected with MAGE-A1 immunotherapy among patients with distal colon cancer under the age of 70.

Reduced p16 expression correlates with lymphatic invasion in colorectal cancers.

BACKGROUND/AIMS: P16, the tumor suppressor gene, plays a crucial role in the most important regulatory pathway involved in the G1/S transition, but its role in gastrointestinal neoplasia remains unclear. METHODOLOGY: To evaluate the possible p16 role in the development of colonic neoplasms, the authors studied p16 immunohistochemical expression of 84 lesions of colorectal cancers, 6 lesions of hyperplastic polyps, 59 lesions of adenomas and 8 lesions of carcinoma in adenoma. Immunohistochemical staining was processed by streptavidin biotin technique. The degree of expression pattern was classified into four types: absent, scattered, or nested, diffuse. Also, the correlation between immunohistochemical expression pattern and clinicopathological features was evaluated. RESULTS: Compared with normal colonic mucosa, in which virtually no p16 expression was observed, p16 was overexpressed in hyperplastic polyps (33%:2/6) adenomas (46%:27/59), carcinoma in adenoma (88%:7/8) and in adenocarcinomas (98%:82/84). In colorectal cancers, when divided into positive (diffuse or nested) and negative (absent or scattered) subgroups, the negative group showed a higher ratio of lymphatic infiltration (p = 0.04), a higher ratio of deeper invasion (p < 0.01) and a higher ratio showing histology of mucinous carcinoma or poorly differentiated adenocarcinoma (p < 0.01). CONCLUSIONS: In colorectal cancers, a significant correlation of reduced p16 expression and lymphatic invasion was observed, which suggested and colorectal cancers with reduced p16 expression have more aggressive potential of lymphatic infiltration. Also a significant correlation between the overexpression of p16 and tumor progression was demonstrated.

The Immunohistochemical expression of endothelial cell differentiation gene-2 receptor in human colorectal adenomas.

BACKGROUND/AIMS: The EDG-2 (endothelial cell differentiation gene-2) has been characterized as one of the high-affinity receptors of lysophosphatidic acid: an extracellular lipid mediator which can induce tumor progression. Recent studies have revealed that EDG-2 plays an important role in various pathological events including cell proliferation and tumor development. The investigation of EDG-2 is thus considered important for eliciting the mechanism of tumorigenesis. However, in colorectal tissue, the clinical significance of EDG-2 expression remains unclear. In the current study, we examined the immunohistochemical expression of EDG-2 in colorectal mucosa and adenoma, and clarified its relation with the clinicopathological features. METHODOLOGY: One hundred and sixty-one colorectal polyps were resected endoscopically or surgically at our institute from 2000 to 2001. According to the degree of dysplasia, adenomas were grouped into two categories: low-grade (mild or moderate dysplasia) and high-grade (severe dysplasia or carcinoma in situ). We investigated EDG-2 expression by immunohistochemistry. RESULTS: EDG-2 was expressed almost exclusively in the cytoplasm in colorectal normal mucosa and adenoma. EDG-2 expression in normal mucosa and adenoma was 8% and 76%, respectively. EDG-2 expression was increased in low-grade adenoma compared with that in normal mucosa (P < 0.001). EDG-2 expression was significantly greater in adenomas with larger diameters (P < 0.001). CONCLUSIONS: We demonstrated that EDG-2 expression was increased in the early stage of adenoma. A significant correlation between EDG-2 expression and the size of the adenomas suggests that EDG-2 may play an important role in the growth of these adenomas.

The usefulness of immunohistochemical evaluation of dihydropyrimidine dehydrogenase for rectal cancer treated with preoperative radiotherapy.

BACKGROUND/AIMS: DPD (dihydropyrimidine dehydrogenase) activity shows a correlation with 5-fluorouracil chemosensitivity. To quantify DPD activity is important for selection of chemosensitive cases of not only sporadic colorectal cancer but also rectal cancer with preoperative radiotherapy. However, it is not cost-effective. We investigated the relation between the immunohistochemical expression pattern of DPD and its activity in rectal cancer treated with radiotherapy, and compared the immunohistochemical DPD expression pattern of preradiation biopsy specimens with that of resected tissues. METHODOLOGY: DPD expression pattern of preradiation biopsy specimens were compared with that of resected tissues. Eighteen colorectal cancer tissue samples were obtained after surgery from October 2000 to January 2001. DPD activity was quantified by sandwich enzyme-linked immunosorbent assay. The streptoavidin-biotin peroxidase complex technique was used for the immunohistochemical expression pattern. RESULTS: DPD was stained in the cytoplasm of cancer cells. There was a significant correlation between the immunohistochemical expression pattern of DPD and its activity in tumor tissue treated with or without radiotherapy. The immunohistochemical expression pattern of preradiation biopsy specimens was almost the same as that of resected tissues. CONCLUSIONS: The immunohistochemical expression pattern of DPD correlated with its activity in tumor tissue treated with preoperative radiotherapy. Immunohistochemical evaluation is considered to be an effective method of predicting the sensitivity to 5-fluorouracil of rectal cancer treated with preoperative radiotherapy.

The expression pattern of Ku correlates with tumor radiosensitivity and disease free survival in patients with rectal carcinoma.

BACKGROUND: Preoperative radiotherapy reduces the rate of local recurrence and improves the chance of survival in patients with resectable, advanced rectal carcinoma. However, because not all tumors respond similarly to radiation, sorting out suitable patients is required to irradiate tumors rationally. The authors examined the possible role of Ku protein in determining tumor radiosensitivity and disease free survival in patients with rectal carcinoma. METHODS: The authors studied 96 patients with advanced rectal carcinoma. In preradiation biopsy specimens of tumor samples, the number of cells that were stained positive for Ku protein was evaluated by immunohistochemistry. The expression pattern of Ku protein was examined for an association between tumor radiosensitivity (which was determined according to T classification downstaging, complete pathologic response, or Response Evaluation Criteria in Solid Tumors) and disease free survival. RESULTS: There was a high degree of correlation between the percentage of cells that expressed the 70-kDa Ku protein (Ku70) and the 86-kDa Ku protein (Ku86) in the tumor sections (correlation coefficient = 0.85; P < 0.001). The expression pattern of Ku protein was correlated not only with tumor radiosensitivity but also with disease free survival. Pathologic TMN classification, histopathologic grade, and Ku70 expression were significant prognostic variables for disease free survival in a multivariate analysis (P = 0.0031, P = 0.030, and P = 0.023, respectively). CONCLUSIONS: Ku70 and Ku86 raise the predictive possibility of tumor radiosensitivity. Ku may be a useful parameter for selecting patients with rectal carcinoma for preoperative radiotherapy.

Extended lymphadenectomy and preoperative radiotherapy for lower rectal cancers.

BACKGROUND: Extended lymphadenectomy including lateral node dissection (EXT-L) contributes to a low incidence of local recurrence of lower rectal cancer. However, EXT-L is frequently associated with impairment of sexual and urinary function. We therefore compared the effectiveness of preoperative radiotherapy with that of EXT-L. METHODS: One hundred fifteen patients were studied. Seventy-eight patients underwent preoperative radiotherapy with a total dose of 50 Gy (Rad[+] group), and 37 did not (Rad[-] group). Seventy-five patients received EXT-L (EXT-L[+] group), and 40 did not (EXT-L[-] group). Patients were further divided into 4 subgroups (Rad[+]&EXT-L[-], Rad(+)&EXT-L[+], Rad[-]&EXT-L(+), and Rad[-]&EXT-L[-]), and clinicopathologic features were examined. In the Rad(+) group, the relation between the p53 gene and survival was also examined. RESULTS: There was a significant difference in disease-free survival between the Rad(+) and Rad(-) groups (5-year disease-free survival rate, 74.6% vs 45.9%; P =.006). However, there was no significant difference between the Rad(+)&EXT-L[-] and Rad[-]&EXT-L(+) groups. The p53 gene status did not affect survival in the Rad(+) group. CONCLUSIONS: This study suggests that in terms of curative effect, preoperative radiotherapy can be one alternative therapy in place of EXT-L for patients with lower rectal cancer.