Hiroyuki Uetake

ERCC1 and Thymidylate Synthase mRNA Levels Predict Survival for Colorectal Cancer Patients Receiving Combination Oxaliplatin and Fluorouracil Chemotherapy

PURPOSE To test the hypotheses of whether the relative mRNA expression of the thymidylate synthase (TS) gene and the excision cross-complementing (ERCC1) gene are associated with response to and survival of fluorouracil (5-FU)/oxaliplatin chemotherapy in metastatic colorectal cancer. PATIENTS AND METHODS Patients had progressive stage IV disease after unsuccessful 5-FU and irinotecan chemotherapy. All patients were evaluated for eligibility for a compassionate 5-FU/oxaliplatin protocol. cDNA was derived from paraffin-embedded tumor specimens to determine TS and ERCC1 mRNA expression relative to the internal reference gene beta-actin using fluorescence-based, real-time reverse transcriptase polymerase chain reaction. RESULTS The median TS gene expression level from 50 metastasized tumors was 3.4 x 10(-3) (minimum expression, 0.18 x 10(-3);maximum expression, 11.5 x 10(-3)), and the median ERCC1 gene expression level was 2.53 x 10(-3) (minimum, 0.0; maximum, 14.61 x 10(-3)). The gene expression cutoff values for chemotherapy nonresponse were 7.5 x 10(-3) for TS and 4.9 x 10(-3) for ERCC1. The median survival time for patients with TS <or= 7.5 x 10(-3) (43 of 50 patients) was 10.2 months, compared with 1.5 months for patients with TS greater than 7.5 x 10(-3) (P < .001). Patients with ERCC1 expression <or= 4.9 x 10(-3) (40 of 50 patients) had a median survival time of 10.2 months, compared with 1.9 months for patients with ERCC1 expression greater than 4.9 x 10(-3) (P < .001). A TS of 7.5 x 10(-3) segregated significantly into response, stable disease, and progression (P = .02), whereas the association between ERCC1 and response did not reach statistical significance (P = .29). CONCLUSION These data suggest that intratumoral ERCC1 mRNA and TS mRNA expression levels are independent predictive markers of survival for 5-FU and oxaliplatin combination chemotherapy in 5-FU-resistant metastatic colorectal cancer. Precise definition of the best TS cut point will require further analysis in a large, prospective study.

Cyclooxygenase-2 Expression A Significant Prognostic Indicator for Patients With Colorectal Cancer

Purpose: Recent studies have shown that cyclooxygenase (Cox)-2 may be involved in colorectal carcinogenesis. We aimed to determine whether Cox-2 expression in itself can predict outcome of colorectal cancer patient after surgery. In addition, the expression of Cox-1 was also evaluated. Experimental Design: Tissue samples of primary and secondary tumors from 288 patients undergoing surgical resections for colorectal adenocarcinoma were immunohistochemically examined for Cox-2 and Cox-1 expressions. The specimens were graded based on the intensity and extent of staining; then, the correlations between Cox-2 and Cox-1 expressions with clinicopathologic parameters and survival time were analyzed. Results: Expression of Cox-2 was positive in 70.8% of primary tumor, 92.0% of lymph node metastases, 100.0% of hepatic metastases, and was significantly associated with tumor size, depth of invasion, lymph node metastasis, vessels invasion, stage and recurrence. In contrast, Cox-1 was positive in 42.7% of primary tumor, 84.0% of lymph node metastases, 37.5% hepatic metastases, and was associated with only tumor size. Patients with Cox-2–positive tumors had a significant shorter survival time than those with negative tumors did (P = 0.0006 by log-rank test); and, in a multivariate analysis, Cox-2 was an independent prognostic factor (P = 0.0103; relative risk 4.114; 95% confidence interval, 1.397–12.120). Cox-1 status had no statistically effect on patient survival time. Conclusions: Elevated Cox-2 expression, but not that of Cox-1, was significantly associated with reduced survival and recognized as an independent prognostic factor in our cohort of colorectal cancer patients.

Clinical Significance of High Mobility Group A2 in Human Gastric Cancer and Its Relationship to let-7 MicroRNA Family

Purpose: The high mobility group A2 (HMGA2) nonhistone chromosomal protein can modulate transcription by altering chromatin architecture. HMGA2 is highly expressed during embryogenesis and in various benign and malignant tumors. Recent studies report that HMGA2 is negatively regulated by the let-7 microRNA (miRNA) family. However, no studies have examined the clinical significance of HMGA2 and its relationship to the let-7 miRNA family in gastric cancer. Experimental Design: Using quantitative real-time reverse transcription–PCR, we analyzed HMGA2 expression with respect to various clinicopathologic factors in 110 patients with gastric cancer. We also did an association study comparing HMGA2 expression and let-7 miRNA family expression in gastric cancer. Results: Expression of HMGA2 in cancerous tissues was significantly higher than in noncancerous tissues (P < 0.05). Elevated HMGA2 expression was significantly correlated with serosal invasion (P < 0.05) and poor clinical prognosis (P < 0.05). A multivariate analysis showed that HMGA2 expression status was an independent prognostic factor (P < 0.05). An inverse correlation between HMGA2 and let-7a was found in gastric cancer cell lines (P = 0.08). The expressions of let-7a, let-7b, and let-7c in gastric cancer patients with low HMGA2 expression were significantly higher than those with high HMGA2 expression (P < 0.05). Conclusions: High expression of HMGA2 in gastric cancer correlates with tumor invasiveness and is an independent prognostic factor. Furthermore, our findings suggest that HMGA2 is negatively regulated by the let-7 miRNA family in human gastric cancer.

Lactate Dehydrogenase-5 (LDH-5) Expression in Human Gastric Cancer: Association with Hypoxia-Inducible Factor (HIF-1α) Pathway, Angiogenic Factors Production and Poor Prognosis

BackgroundLactate-dehydrogenase-5 (LDH-5) is an important isoenzyme converting pyruvate to lactate under hypoxic conditions and might play an important role in the development and progression of malignancies. However, the role of LDH-5 in gastric cancer is still unclear. In this study, we investigated the clinical significance of LDH-5 expression in gastric carcinoma.MethodsLDH-5 expression in 152 patients with different grade and stage gastric carcinoma was analyzed by immunohistochemistry. In addition, hypoxia-inducible factor 1α (HIF-1α) as a marker of tumor hypoxia, as well as vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) as angiogenesis parameters were also assessed in this study. Correlations between the expression of investigated proteins and various clinicopathological factors including survival were determined.ResultsThere were 94 cases (61.8%) showing high LDH-5 expression, and 95 patients (62.5%) had high HIF-1α expression. Positive correlation was found between LDH-5 expression and HIF-1α, VEGF, and COX-2. The overexpression of LDH-5 was more prevalent in advanced tumors having positive vessel invasion. Patients with overexpression of LDH-5 showed far lower disease-free (63.5% vs 82.7%) and overall (56.3% vs 78.4%) survival rates compared with patients with low LDH-5 expression. HIF-1α expression was shown to have no significance on survival. In multivariate analysis, high LDH-5 expression kept its independence as a negative prognostic indicator.ConclusionThe results of the current study show that LDH-5 expression may be a useful prognostic factor for patients with gastric carcinoma.

PIK3CA mutation is predictive of poor survival in patients with colorectal cancer

The PI3K‐AKT pathway is activated in a variety of human cancers, resulting in disturbance of cell growth, proliferation and survival. Among the factors affecting the pathway, the K‐Ras mutation and PIK3CA mutation are the most common oncogenic alterations in colorectal cancer. We hypothesized that these two mutations are important in activation of the PI3K pathway and colorectal carcinogenesis. In this study, we aimed to examine the influence of PIK3CA mutation and K‐Ras mutation on AKT activation, and to clarify whether PIK3CA mutation, K‐Ras mutation and p‐AKT expression may be used as parameters for predicting prognosis in colorectal cancer. Tissue samples from 158 colorectal cancer patients who underwent surgical resection were examined. The sequences of exon 1 of K‐Ras and exons 9 and 20 of PIK3CA were determined by direct sequencing using genomic DNA extracted from paraffin‐embedded blocks. Activation status of AKT was evaluated by immunohistochemical staining using phospho‐specific AKT antibody (Ser473). Correlation between these factors and clinicopathologic findings/patient survival were examined. As a result, PIK3CA mutation was significantly associated with shorter relapse‐free survival (RFS) in stage II/III patients (p = 0.0216) and shorter disease‐specific survival in all patients (p = 0.0357). In the multivariate analysis, PIK3CA mutation was the only independent and significant prognostic factor for RFS in stage II/III patients (p = 0.0433, HR 2.478). This study revealed the prognostic value of PIK3CA mutation in colorectal cancer patients. Patients with PIK3CA mutation should be followed up carefully. Moreover, our result suggests that inhibition of PIK3CA mutant may be a new molecular target therapy.

Prognostic Significance of VEGF Expression in Correlation With COX-2, Microvessel Density, and Clinicopathological Characteristics in Human Gastric Carcinoma

BackgroundMany studies have shown that angiogenesis plays an important role in the process of cancer development and progression. Vascular endothelial growth factor (VEGF) has a potent angiogenic activity, and cyclooxygenase-2 (COX-2) supports angiogenesis by regulated production of angiogenic factors, including VEGF. The purpose of this study was to examine the expression of VEGF in combination with COX-2 and CD34, their correlation with various clinicopathological factors, and their prognostic significance in human gastric carcinoma.MethodsSpecimens from 169 patients with different grade and stage gastric carcinoma were investigated by immunohistochemistry for COX-2 and VEGF expression. Tumor microvessel density was assessed with CD34 immunostaining. Correlations between the expression of VEGF, COX-2, CD34, and various clinicopathological factors were studied. The effect of these proteins on patient survival was determined.ResultsCOX-2 and VEGF were positively expressed in 36.7% and 50.3% of the patients, respectively. Positive correlation was found between VEGF and COX-2 and between VEGF and CD34. VEGF expression was correlated with depth of invasion; metastatic lymph nodes; lymphatic and venous invasion; and tumor, node, metastasis system stage. Patients with positive staining for VEGF showed far lower disease-free (64.9% vs. 81.3%) and overall (58.3% vs. 76.9%) survival rates than VEGF-negative patients. In multivariate analysis, only tumor location, depth of invasion, and lymph node metastasis were shown to be independent prognostic factors.ConclusionsVEGF expression correlates with angiogenesis and tumor progression and is a valuable prognostic factor in patients with gastric carcinoma.

Methylated TMS1 and DAPK genes predict prognosis and response to chemotherapy in gastric cancer.

Gastric cancer is the second most common cause of cancer deaths worldwide. The identification of molecular genetic parameters that are associated with response to chemotherapy and prognosis is of utmost interest. We examined methylation of the apoptosis‐related genes, TMS1 and DAPK, in 81 primary gastric cancers using methylation‐specific PCR and compared their methylation status with clinicopathological findings. Aberrant methylation of TMS1 and DAPK genes was detected in 26 (32.1%) tumors and in 18 (22.2%) tumors, respectively. The overall survival of patients with both methylated genes was significantly shorter compared with those with only one methylated gene or no methylated genes (p = 0.0003). Neither gene methylation had any relation to other clinicopathological findings. Next, we examined 43 patients treated by 5‐fluorouracil–based chemotherapy, who had distant metastasis or recurrence after radical resection, to determine the relation between chemosensitivity and methylation. The response rate was lower in patients with either methylation than without (TMS1: 22.2% vs. 48.0%; DAPK: 21.4% vs. 44.8%). Overall survival tended to be shorter in the patients with both methylations compared with either or no methylations (p = 0.0806). The time to progression of patients with methylation of TMS1 or DAPK was significantly shorter than patients without methylation (TMS1: p = 0.0123; DAPK: p = 0.0464). Furthermore, the time to progression of patients with both methylated genes was significantly shorter than patients with one methylation or no methylation (p = 0.0082). In conclusion, TMS1 and DAPK methylation might predict the prognosis and response to chemotherapy in gastric cancer.

Clinical Significance of Osteoprotegerin Expression in Human Colorectal Cancer

Purpose: This study aimed to identify a novel biomarker or a target of treatment for colorectal cancer (CRC). Experimental Design: The expression profiles of cancer cells in 104 patients with CRC were examined using laser microdissection and oligonucleotide microarray analysis. Overexpression in CRC cells, especially in patients with distant metastases, was a prerequisite to select candidate genes. The mRNA expression of candidate genes was investigated by quantitative reverse transcriptase PCR (RT-PCR) in 77 patients as a validation study. We analyzed the protein expression and localization of the candidate gene by immunohistochemical study and investigated the relationship between protein expression and clinicopathologic features in 274 CRC patients. Results: Using microarray analysis, we identified 6 candidate genes related to distant metastases in CRC patients. Among these genes, osteoprotegerin (OPG) is known to be associated with aggressiveness in several cancers through inhibition of apoptosis via neutralization of the function of TNF-related apoptosis-inducing ligand. The mRNA expression of OPG in cancer tissues was significantly higher in patients with distant metastases than those without metastases. Overexpression of OPG protein was associated with significantly worse overall survival and relapse-free survival. Moreover, overexpression of the OPG protein was an independent risk factor for CRC recurrence. Conclusion: Overexpression of OPG may be a predictive biomarker of CRC recurrence and a target for treatment of this disease. Clin Cancer Res; 17(8); 2444–50. ©2011 AACR.

Methylation of BNIP3 and DAPK indicates lower response to chemotherapy and poor prognosis in gastric cancer

Aberrant promoter hypermethylation (methylation) is an epigenetic change that silences the expression of crucial genes, thus inactivating the apoptotic pathway in various cancers. Inactivation of the apoptotic pathway has been considered to be associated with chemoresistance. The objective of the present study was to clarify the effect of the methylation of the apoptosis-related genes, Bcl-2/adenovirus E1B 19 kDa-interacting protein 3 (BNIP3) and death-associated protein kinase (DAPK), on the response to chemotherapy in metastatic or recurrent gastric cancers. Tumor samples were obtained from 80 gastric cancer patients who were treated with fluoropyrimidine-based chemotherapy for distant metastatic or recurrent disease, after surgical resection of the primary tumor. The methylation status of the apoptosis-related genes, BNIP3 and DAPK, was investigated by methylation-specific PCR. Methylation in BNIP3 was detected in 31 tumors (39%) and in DAPK in 33 tumors (41%). There was no correlation between the methylation status of BNIP3 and that of DAPK. The response rate was significantly lower in patients with methylation of DAPK, than in those without (21 vs. 49% p=0.012). Progression-free survival time (PFS) was shorter in patients with methylation of DAPK than in those without (p=0.007). The overall survival time (OS) was shorter in patients with methylation of BNIP3 than in those without (p=0.031). The response rate was significantly lower in patients with methylation of either DAPK or BNIP3, or both, than in those without methylation (p=0.003). PFS and OS were significantly shorter in patients with methylation of either or both of these genes than in those without (p=0.002, p=0.001). The methylation of BNIP3 and DAPK can predict lower response to chemotherapy and poor prognosis in gastric cancer.

MUC12 mRNA expression is an independent marker of prognosis in stage II and stage III colorectal cancer

Distant metastasis is the major cause of death in colorectal cancer (CRC) patients. To identify genes influencing the prognosis of patients with CRC, we compared gene expression in primary tumors with and without distant metastasis using an oligonucleotide microarray. We also examined the expression of the candidate gene in 100 CRC patients by quantitative real‐time reverse transcription PCR and studied the relationship between its expression and the prognosis of patients with CRC. As a result, we identified MUC12 as a candidate gene involved in metastasis processes by microarray analysis. Quantitative real‐time reverse transcription PCR showed that MUC12 expression was significantly lower in cancer tissues than in adjacent normal tissues (p < 0.001). In Stages II and III CRC, patients with low expression showed worse disease‐free survival (p = 0.020). Multivariate analysis disclosed that MUC12 expression status was an independent prognostic factor in Stages II and III CRC (relative risk, 8.236; 95% confidence interval, 1.702–39.849 p = 0.009). Our study revealed the prognostic value of MUC12 expression in CRC patients. Moreover, our result suggests MUC12 expression is a possible candidate gene for assessing postoperative adjuvant therapy for CRC patients.