Minichromosome maintenance protein 7 is a risk factor for recurrence in patients with Dukes C colorectal cancer

BACKGROUND

It has been hypothesized that minichromosome maintenance (MCM) proteins, which are replicative control factors, can be used to detect tumor proliferation. The aim of the present study was to investigate the expression of MCM in colorectal cancer tissues and correlate it to clinical outcomes.

PATIENTS AND METHODS

The study included 145 patients with colorectal cancer who underwent curative surgery, from January 2002 until December 2004, at the Kurume University Hospital in Fukuoka, Japan. The median follow-up duration was 87 months. The expression of MCM7 in tissues was studied by immuno-histochemical staining. The labeling index (LI) of MCM7 was calculated by dividing the number of positively-stained cells by the total number of cells counted. We divided samples into two groups: positive (MCM7 LI 76% or higher) and negative (MCM7 LI less than 76%).

RESULTS

In patients with Dukes A and B, there were no significant differences in either overall survival (OS) or recurrence-free survival (RFS) between patents with MCM7-positive and those with MCM7-negative disease. On the other hand, in patients with Dukes C, there was significantly worse OS and RFS for patients with MCM7-positive compared to those with MCM7-negative disease.

CONCLUSION

We found that the expression of MCM7 is an independent risk factor for RFS in patients with Dukes C colorectal cancer. Further studies are required to investigate the validity of MCM7 protein expression for its potential clinical use in colorectal cancer therapy and prognosis.

Expression of monocarboxylate transporter (MCT)-4 in colorectal cancer and its role: MCT4 contributes to the growth of colorectal cancer with vascular endothelial growth factor

BACKGROUND

In tumor cells, monocarboxylate transporter (MCT)-4 regulates the excretion of lactate produced by glycolysis from the cell. MCT4 has also been reported to be involved in tumor growth and infiltration. Similarly, vascular endothelial growth factor (VEGF) is known to be involved in the growth, infiltration, and metastasis of tumors. In this study, we clinically evaluated the relationship between MCT4 and VEGF in colorectal cancer.

MATERIALS AND METHODS

A prospective study was conducted in 210 patients with colorectal cancer who underwent surgical treatment. The clinicopathological data were correlated with the expression of MCT4 and VEGF obtained from immunohistochemical analysis.

RESULTS

MCT4 and VEGF were expressed in tumors of 102 (49%) and 129 (61%) patients, respectively. A maximum tumor diameter of 45 mm or more (p<0.0001) and a tumor invasion depth of T1 or less (p<0.0119) were factors independently correlated with the expression of MCT4 and VEGF, respectively. The tumor size was significantly smaller (p=0.0031), and the disease was significantly less advanced (p=0.0017), in MCT4-negative/VEGF-positive than MCT4-positive/VEGF-negative cases.

CONCLUSION

We suspect that in colorectal cancer, VEGF is involved in the early stages of tumor growth and MCT4 expression appears as the tumor enlarges and contributes to its further infiltration and growth.

Amphiregulin is a prognostic factor in colorectal cancer

Amphiregulin is an epidermal growth factor (EGF) which is a ligand of epidermal growth factor receptor (EGFR). Amphiregulin is the most enhanced EGFR ligand in colon cancer. Here we report on the expression of Amphiregulin using immunohistochemical staining in primary colorectal cancer, and the correlations between prognosis and various clinicopathological factors. We examined 174 consecutive patients who underwent curative resection of colorectal cancer, from January 2002 to December 2004. Amphiregulin was positive in 156 (90%) patients. Amphiregulin was found to be an independent predictor of overall survival [hazard ratio=6.25 (95% confidence interval=1.3-111.5; p=0.0144)] and relapse-free survival [hazard ratio=6.94 (95% confidence interval=1.5-123.2; p=0.0075)]. We conclude that the expression of Amphiregulin in a primary colorectal tumor is useful as an indicator of prognosis and as a predictor of recurrence.

Increased claudin-1 protein expression in hepatic metastatic lesions of colorectal cancer

BACKGROUND

The molecular and morphological alterations of the tight junctions in hepatic metastatic lesions are poorly understood. The possible involvement of claudin-1 (CL-1), which is one of the major tight junctional proteins, was investigated in the tumorigenesis of hepatic metastasis in patients with colorectal cancer (CRC).

PATIENTS AND METHODS

A total of 14 patients with hepatic metastasis of CRC who underwent surgical treatment from January 2007 until December 2010 at the Kurume University Hospital in Fukuoka, were examined. CRC tissue specimens were analyzed to determine whether the levels of CL-1 correlated with clinicopathological factors and to determine the roles of CL-1, β-catenin, and E-cadherin in the alterations of the tight junctions during tumorigenesis.

RESULTS

In seven cases, the tumors were located in the colon, while the other seven tumors were found in the rectum. There were eight cases of synchronous liver metastasis, while there were six cases of metachronous liver metastasis. The levels of the CL-1 protein were up-regulated in CRC and in hepatic metastatic lesions. The levels of β-catenin were positive or up-regulated in the primary CRC lesions and in hepatic metastatic lesions. Despite the finding that the levels of E-cadherin were decreased in CRC, they were clearly up-regulated in hepatic metastatic lesions in this study.

CONCLUSION

This study demonstrated that CL-1 levels were up-regulated in liver metastatic lesions from primary CRC lesions. Moreover, the levels of E-cadherin were increased in liver metastatic lesions, which may point to the existence of interactions between CL-1 and E-cadherin in hepatic metastatic lesions. These observations suggest that CL-1 plays a pivotal role in the regulation of cellular morphology and in the behavior of metastatic processes in CRC.

Expression of IGF-1 and IGF-1R and their relation to clinicopathological factors in colorectal cancer

BACKGROUND

Expression of insulin-like growth factor-1 (IGF-1) and IGF-1 receptor (IGF-1R) has been shown to increase in colorectal cancer. We examined the correlation between expression of IGF-1 and IGF-1R and clinicopathological factors in colorectal cancer.

PATIENTS AND METHODS

A prospective study was conducted of 210 colorectal cancer patients that underwent resection from January 2002 to December 2004. The clinicopathological data was correlated to expression of IGF-1 and IGF-1R obtained from immunohistochemical analysis. Statistical analysis was carried using univariate and multivariate analysis.

RESULTS

IGF1 and IGF-1R staining was positive in 169 (80%) and 139 (66%) cases, respectively. Univariate and multivariate analyses showed significant correlation between expression of IGF-1 and tumor size (p=0.0024), and depth of invasion (p=0.0147). While IGF-1R was significantly correlated to tumor size and depth of invasion in univariate analysis, only tumor size (p=0.0658) had a strong association in multivariate analysis.

CONCLUSION

Expression of IGF-1 and IGF-1R seems to increase with tumor size in colorectal cancer.

Decreased expression of claudin-1 in rectal cancer: a factor for recurrence and poor prognosis

AIM

To investigate the potential involvement of claudin-1 (CL-1) in the tumorigenesis of rectal cancer by analyzing the correlation between CL-1 expression, clinicopathological factors and prognosis.

PATIENTS AND METHODS

Rectal cancer tissue specimens from 306 patients that had undergone surgical treatment were evaluated using immunohistochemical analysis for expression of CL-1 and correlated with clinicopathological factors.

RESULTS

A reduced expression of CL-1 (less than 30% of tumor cells strongly, positively stained) correlated significantly with poor prognosis in stage II and III rectal cancer. Moreover, the expression levels of CL-1 correlated significantly with tumor differentiation and perineural invasion (p=0.037 and 0.009, respectively). However, no significant differences were detected between the expression levels of CL-1 and other clinicopathological factors.

CONCLUSION

Loss of claudin-1 expression is a strong predictor of disease recurrence and poor patient survival in stage II and III rectal cancer.

[Therapeutic results of hepatic resection using thermal ablation for unresectable colorectal liver metastases]

We have retrospectively reviewed the therapeutic results of hepatic resection with or without thermal ablation therapy (TA) for colorectal liver metastases in 138 patients between 1994 and 2006. A total of 88 unresectable liver metastatic lesions were selectively treated with TA as initial treatment (42 patients) basically in combination with hepatectomy. Overall, TA achieved a high local tumor control rate of 94.3%. Multivariate analysis revealed that initial TA therapy was not a significantly predictive factor of hepatic recurrence or any recurrence. TA therapies in combination with hepatectomy may offer improving resectability without risk to intrahepatic dissemination or to extrahepatic recurrence.

A new method of concentrating hepatitis B virus (HBV) DNA and HBV surface antigen: an application of the method to the detection of occult HBV infection

BACKGROUND

The risk of post-transfusion hepatitis B virus (HBV) infection has been reduced after the implementation of HBV nucleic acid amplification technology (NAT). However, the problem of HBV DNA-positive and HBV surface antigen (HBsAg)-negative occult HBV infections remains to be solved. This is in part due to the HBV DNA load being too low to detect these occult HBV infections using mini-pool NAT. In Japan, the assay for the antibody against the HBV core antigen (anti-HBc) has not completely excluded occult HBV infection. To solve this problem, we have developed a new method of concentrating HBV DNA and HBsAg simultaneously to increase the sensitivity of detection tests.

METHODS

Virus concentration is achieved by the enhancement of the agglutination of viruses using poly-L-lysine in the presence of a bivalent metal. Poly-L-lysine-coated magnetic beads are used to shorten the time of each step of the concentration procedure. Seventy-seven anti-HBc-positive and HBsAg-negative donations were examined. HBsAg and anti-HBc were tested by enzyme immunoassay (EIA) (AxSYM; Abbott) and haemagglutination inhibition test (Japanese Red Cross), respectively.

RESULTS

HBV surface antigen and HBV DNA levels were concentrated up to four- to sevenfold. Using this method, 35 of the 77 anti-HBc-positive and HBsAg-negative donors were HBV DNA-positive by individual NAT and a further five donors became HBV DNA-positive by HBV concentration. Twenty-seven of 40 occult HBV infections became HBsAg-positive by HBsAg concentration.

CONCLUSION

Our new method of concentrating HBV and HBsAg increased the sensitivities of EIA and HBV NAT, and enabled us to detect 27 of 40 occult HBV infections by HBsAg EIA.