ERCC2 2251A>C genetic polymorphism was highly correlated with early relapse in high-risk stage II and stage III colorectal cancer patients: a preliminary study

Effects of various genetic polymorphisms on thiopurine treatment-associated outcomes for Korean patients with Crohn's disease

AIMS

This study explores the effects of various genetic polymorphisms in candidate genes on thiopurine metabolism and toxicity in adult patients with Crohn's disease in Korea.

METHODS

A total of 131 adult patients with Crohn's disease receiving thiopurine treatment were included. The TPMT and NUDT15 genes and an additional 116 genetic polymorphisms (in 40 genes and 3 intergenic locations) were screened for genotyping. Among the polymorphisms screened, 91 genetic polymorphisms (in 34 genes and 3 intergenic locations) in addition to TPMT and NUDT15 genotypes were included for statistical analyses to investigate their effects on thiopurine metabolites and adverse outcomes (leukopenia, hepatotoxicity, gastrointestinal intolerance, skin rash and alopecia).

RESULTS

The median duration of thiopurine treatment was 47.0 months (range 6.0-153.4 months). Patient sex, maintenance dose of thiopurine, and use of anti-tumour necrosis factor agents were associated with thiopurine metabolite concentrations (P < .05). In the univariate analysis, the TPMT genotype was associated with 6-thioguanine level (P < .05), although the significance of this did not remain in multivariate analysis. Genetic polymorphisms in the ATIC (rs3821353 and rs16853834), IMPDH2 (rs11706052) and ITPA (rs6139036) genes were associated with thiopurine metabolism (P < .05). Genetic polymorphisms in the ABCC5 (rs8180093) and NUDT15 genotypes were associated with leukopenia (P < .05).

CONCLUSION

The results of this study may help clinicians to understand the effects of other various polymorphisms in addition to TPMT and NUDP15 in thiopurine metabolism for management of Crohn's disease patients.

Colorectal cancer: pharmacogenetics support for the correct drug prescription

Pharmacogenetics (PGx) in clinical practice is a tool that the clinician can use to guide, in a personalized way, the most suitable treatment that will be administered to the patient. The objective of this review is to summarize in a practical and accessible rational way, the advances that currently exist for the application of PGx in colorectal cancer chemotherapy management through the study of the patients' germline polymorphisms. To define the polymorphisms that can be applied, we rely on three fundamental cornerstones: the recommendations of drug regulatory agencies; the implementation guidelines prepared by expert consortia in PGx and information from clinical annotations (the drug/polymorphism relation) according to the scientific level of evidence assigned by PharmGKB experts.

Pathway genes and metabolites in thiopurine therapy in Korean children with acute lymphoblastic leukaemia

AIMS

We aimed to investigate the impact of various genetic polymorphisms affecting thiopurine metabolism pathways and toxicity in paediatric acute lymphoblastic leukaemia patients for the first time in Korea.

METHODS

From May 2006 to September 2016, 139 paediatric acute lymphoblastic leukaemia patients treated with combination chemotherapy including 6-mercaptopurine were included in the study. One hundred and twenty-three variants in 43 genes, including TMPT and NUDT15, were screened using targeted genotyping, such as a MassARRAY system, direct sequencing and polymerase chain reaction-restriction fragment length polymorphism methods. Among the polymorphisms screened, 103 polymorphisms of 43 genes were included for further analyses.

RESULTS

The genetic polymorphisms in the ABCC4, AHCY, ATIC, FAM8A6P, GART, GNG2, GSTA1, MTHFD1, MTHFR, NUDT15, PACSIN2, TYMS and XDH genes, and an intronic polymorphism between HIVEP2 and AIG1, and TPMT genotype were associated with thiopurine metabolism (P < 0.05). Genetic polymorphisms in the ABCC4, ADK, ATIC, GART, GMPS, GSTP1, IMPDH1, ITPA, KCNMA1, MOCOS, MTRR, NUDT15, SLC19A1, SLC28A3, SLC29A1, SLCO1B1, TYMP and XDH genes were associated with thiopurine-related toxicities; neutropenia, hepatotoxicity and treatment interruption (P < 0.05).

CONCLUSIONS

Findings of this study may provide basic knowledge for personalized medicine for thiopurinxe treatment in paediatric acute lymphoblastic leukaemia patients.

A Pharmacogenetic Study of VDR fok1 and TYMS Polymorphisms and Their Association With Glucocorticoid-Induced Osteonecrosis in Egyptian Children With Acute Lymphoblastic Leukemia

Purpose: Osteonecrosis is a significant toxicity resulting from the treatment of pediatric Acute Lymphoblastic Leukemia (ALL). This study aimed to investigate the relationship between vitamin D receptor fok1 (VDR fok1) and thymidylate synthase (TYMS) gene polymorphisms with the glucocorticoid (GC) induced osteonecrosis (ON) in Egyptian pediatric ALL patients. In addition, to identify the possible association of genetic polymorphisms with other factors such as gender and ALL subtypes.

Patients and Methods: A retrospective case-control study was conducted on 102 pediatric ALL patients under the age of 18 who were treated at Children Cancer Hospital Egypt according to St Jude SR/HR total XV protocol. The recruited patients were composed of 51 cases who developed GC-induced osteonecrosis and 51 age- and gender-matched patients who received glucocorticoids but remained osteonecrosis-free (controls). Genotyping of the VDR fok1 and TYMS genes was performed using restriction fragment length polymorphism (RFLP) and conventional PCR, respectively.

Results: For the total 102 studied patients, the VDR fok1 single nucleotide polymorphisms (SNPs) frequency distribution were TT (8.8%), CT (34.3%), and CC (56.9%), while the TYMS tandem repeat gene variations were reported as 2R2R (20.6%), 2R3R (45.1%), and 3R3R (34.3%). VDR fok1 and TYMS polymorphic variants showed no association neither with gender; P-values 0.3808 and 0.1503, respectively, nor with ALL subtypes; P-values 0.9396 and 0.6596, respectively. The VDR fok1 polymorphisms showed a significant association with the development of ON; P-value = 0.003, on the other hand, TYMS tandem repeats did not show significant impact on osteonecrosis development; P-value = 0.411.

Conclusion: This study showed a significant association between the VDR fok1 polymorphism and osteonecrosis. Such clinical pharmacogenetics results would be promising to discuss the possibility of dose adjustments aiming a regimen with the highest efficacy and least toxicity.

Thymidylate synthase gene variants as predictors of clinical response and toxicity to fluoropyrimidine-based chemotherapy for colorectal cancer

BACKGROUND

Fluoropyrimidines form the chemotherapy backbone of advanced and metastatic colorectal cancer (CRC). These drugs are frequently associated with toxicity events that result in dose adjustments and even suspension of the treatment. The thymidylate synthase (TYMS) gene is a potential marker of response and toxicity to fluoropyirimidines as this enzyme is the molecular target of these drugs. Our aim was to assess the association between variants of TYMS with response and toxicity to fluoropyrimidines in patients with CRC in independent retrospective and prospective studies.

METHODS

Variants namely rs45445694, rs183205964, rs2853542 and rs151264360 of TYMS were genotyped in 105 CRC patients and were evaluated to define their association with clinical response and toxicity to fluoropyrimidines. Additionally, the relationship between genotypes and tumor gene expression was analyzed by quantitative polymerase chain reaction.

RESULTS

The 2R/2R (rs45445694) was associated with clinical response (p=0.05, odds ratio (OR)=3.45) and severe toxicity (p=0.0014, OR=5.21, from pooled data). Expression analysis in tumor tissues suggested a correlation between the 2R/2R genotype and low TYMS expression.

CONCLUSIONS

The allele 2R (rs45445694) predicts severe toxicity and objective response in advanced CRC patients. In addition, the alleles G(rs2853542) and 6bp-(rs151264360) are independent predictors of response failure to chemotherapy. This is the first study made on a Latin American population that points out TYMS gene variants have predictive values for response and toxicity in patients with CRC treated with fluoropyrimidine-based chemotherapy.

Relevance of methylenetetrahydrofolate reductase gene variants C677T and A1298C with response to fluoropyrimidine-based chemotherapy in colorectal cancer: a systematic review and meta-analysis

Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme influencing the metabolism of fluoropyrimidines. The relevance of MTHFR polymorphisms with the clinical response to fluoropyrimidine-based chemotherapy has been explored, but the results remain controversial. Thus, a meta-analysis was performed to provide a comprehensive estimate in this account. Relevant studies were identified through PubMed, Embase and Web of Science databases from inception up to May 2017. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were applied to assess the strength of association. A total of 2118 colorectal cancer patients from 21 studies were included in the meta-analysis. Overall, there was no significant association between MTHFR C677T (rs1801133) or A1298C (rs1801131) polymorphisms and the clinical response to fluoropyrimidine-based chemotherapy under all of the three genetic models (allele model, dominant model, and recessive model) and stratification analysis, except for the retrospective study subgroup in the dominant model of MTHFR C677T and the “5-Fu + FA” treatment group in the allele contrast of MTHFR A1298C. No or moderate heterogeneity was observed in all genetic models. This meta-analysis suggested that MTHFR polymorphisms could not be considered as reliable factors for predicting the clinical response to fluoropyrimidine-based chemotherapy in colorectal cancer patients.

Relationship Between Expression of Proteins ERCC1, ERCC2, and XRCC1 and Clinical Outcomes in Patients with Rectal Cancer Treated with FOLFOX-Based Preoperative Chemoradiotherapy

BACKGROUND

Platinum resistance enhances DNA damage repair through nucleotide excision repair mechanisms involving the excision repair cross-complementing group 1 (ERCC1), X-ray cross-complementing group 1 (XRCC1), and excision repair cross-complementing group 2 (ERCC2). We evaluated the correlation between the expression of these three DNA repair genes and clinical outcomes in patients with rectal cancer receiving FOLFOX-based preoperative chemoradiotherapy (CRT).

METHODS

Using immunohistochemistry, we examined the expression of ERCC1, ERCC2, and XRCC1 in pre-CRT cancer tissues from 86 patients with rectal cancer who had undergone curative resection and preoperative CRT with FOLFOX-4 to identify potential predictors of clinical outcomes.

RESULTS

Following CRT, 57 and 29 patients were classified as responders (pathological tumor regression grade TRG 0 and TRG 1) and poor responders (TRG 2 and TRG 3), respectively. The multivariate analysis revealed that ERCC1 overexpression was correlated with a poor CRT response [p < 0.0001; odds ratio (OR), 9.397; 95% confidence interval (CI) 2.721-32.457]. Furthermore, a poor response to CRT (pathological TRG of 2-3) (p = 0.18; OR 5.685; 95% CI 1.349-23.954) and abnormal pre-CRT serum carcinoembryonic antigen levels (>5 ng/mL) (p = 0.03; OR 6.288; 95% CI 1.198-33.006) were independent predictors of postoperative relapse. By contrast, ERCC2 and XRCC1 expression did not play predictive roles in the analyzed patients.

CONCLUSIONS

ERCC1 overexpression is associated with a poor preoperative CRT response in patients with rectal cancer receiving FOLFOX-based preoperative CRT. ERCC1 is a potential biomarker for identifying patients who can benefit from customized treatment programs.

The Differential Expression of Core Genes in Nucleotide Excision Repair Pathway Indicates Colorectal Carcinogenesis and Prognosis

Background

Nucleotide excision repair (NER) plays a critical role in maintaining genome integrity. This study aimed to investigate the expression of NER genes and their associations with colorectal cancer (CRC) development.

Method

Expressions of NER genes in CRC and normal tissues were analysed by ONCOMINE. The Cancer Genome Atlas (TCGA) data were downloaded to explore relationship of NER expression with clinicopathological parameters and survival of CRC.

Results

ERCC1, ERCC2, ERCC5, and DDB2 were upregulated while ERCC4 was downregulated in CRC. For colon cancer, high ERCC3 expression was related to better T stage; ERCC5 expression indicated deeper T stage and distant metastasis; DDB2 expression suggested earlier TNM stage. For rectal cancer, ERCC2 expression correlated with favourable T stage; XPA expression predicted worse TNM stage. ERCC2 expression was associated with worse overall survival (OS) in colon cancer (HR = 1.53, P = 0.043). Colon cancer patients with high ERCC4 expression showed favorable OS in males (HR = 0.54, P = 0.035). High XPC expression demonstrated decreased death hazards in rectal cancer (HR = 0.40, P = 0.026).

Conclusion

ERCC1, ERCC2, ERCC4, ERCC5, and DDB2 were differently expressed in CRC and normal tissues; ERCC2, ERCC3, ERCC5, XPA, and DDB2 correlated with clinicopathological parameters of CRC, while ERCC2, ERCC4, and XPC might predict CRC prognosis.

EGFR expression in patients with stage III colorectal cancer after adjuvant chemotherapy and on cancer cell function

The epidermal growth factor receptor (EGFR)/RAS/RAF/MEK/MAPK pathway plays a crucial role in the carcinogenesis, invasion and metastasis of colorectal cancer (CRC). However, its role in the prognosis and prediction of relapse in patients with stage III CRC after adjuvant chemotherapy remains controversial. In the present study, the clinicopathological features of 173 patients with stage III CRC who underwent radical resection and adjuvant chemotherapy with the fluoropyrimidine/folinic acid, and oxaliplatin (FOLFOX) regimen, and their prognostic values of EGFR expression were retrospectively analyzed. By conducting an in vitro CRC cell line study through the knockdown of EGFR expression, we analyzed cell proliferation, colony formation and migration. Positive EGFR expression and an abnormal postoperative serum carcinoembryonic antigen (CEA) level were found to be significant independent negative predictive factors for postoperative relapse. Furthermore, positive EGFR expression was a significant independent negative prognostic factor for disease-free survival (DFS) and overall survival (OS). Additionally, an in vitro cell line study showed that the knockdown of EGFR expression significantly reduced CRC cell proliferation, colony formation and migration. The results of in vitro and in vivo experiments demonstrated that EGFR expression had a prognostic value for OS and DFS, as well as predictive roles for postoperative relapse, in patients with stage III CRC. By analyzing both EGFR expression and the postoperative CEA, the patients with stage III CRC who were at a high risk of postoperative relapse, or mortality following adjuvant chemotherapy could be identified. In short, CRC cells with EGFR expression would exhibit a highly malignant behavior.

Polymorphisms in nucleotide excision repair genes and risk of primary prostate cancer in Chinese Han populations

Genetic variants of nucleotide excision repair (NER) genes have been extensively investigated for their roles in the development of prostate cancer (PCa); however, the published results have been inconsistent. In a hospital-based case-control study of 1,004 PCa cases and 1,055 cancer-free controls, we genotyped eight potentially functional single nucleotide polymorphisms (SNPs) of NER genes (i.e., XPC, rs2228001 T>G and rs1870134 G>C; XPD, rs13181 T>G and rs238406 G>T; XPG, rs1047768 T>C, rs751402 C>T, and rs17655 G>C; and XPF, rs2276464 G>C) and assessed their associations with risk of PCa by using logistic regression analysis. Among these eight SNPs investigated, only XPC rs1870134 CG/CC variant genotypes were associated with a decreased risk of prostate cancer under a dominant genetic model (adjusted odds ratio [OR] = 0.77, 95% confidence interval [CI] = 0.64-1.91, P = 0.003). Phenotype-genotype analysis also suggested that the XPC rs1870134 CG/CC variant genotypes were associated with significantly decreased expression levels of XPC mRNA in a mix population of different ethnicities. These findings suggested that XPC SNPs may contribute to risk of PCa in Eastern Chinese men.

Nucleotide excision repair and response and survival to chemotherapy in colorectal cancer patients

Several new chemotherapeutic agents have become available for the treatment of colorectal cancer, which has led to increased complexity in treatment planning. Treatment decision making for individual patients could be facilitated if guided by predictive and prognostic markers. As most cytotoxic drugs induce DNA damage, the DNA damage repair pathways hold potential for yielding such biomarkers. Here, we review the current evidence of a possible involvement of the nucleotide excision repair pathway in the efficacy of chemotherapeutic agents used in the treatment of colorectal cancer. Although a large number of studies have been conducted, they are generally of moderate size and heterogeneous in design. Up to date no firm conclusions can be drawn to translate these results into the clinic. We recommend further comprehensive investigations of the nucleotide excision repair pathway in large patient studies that include both discovery and validation cohorts.

Impact of Genetic Polymorphisms on 6-Thioguanine Nucleotide Levels and Toxicity in Pediatric Patients with IBD Treated with Azathioprine

BACKGROUND

Thiopurine-related toxicity results in discontinuation of therapy in up to 30% of patients with inflammatory bowel disease. Although thiopurine S-methyltransferase (TPMT) is implicated in toxicity, not all toxicity can be attributed to TPMT polymorphisms. We investigated the effects of polymorphisms of genes involved in thiopurine and folate metabolism pathways on 6-thioguanine nucleotide levels and toxicity.

METHODS

Retrospective clinical data and blood samples were collected from 132 pediatric patients with inflammatory bowel disease treated with azathioprine. Eighty-seven genetic polymorphisms of 30 genes were screened using the MassARRAY system, and 70 polymorphisms of 28 genes were selected for further analysis.

RESULTS

TPMT genotype (P < 0.001), concurrent use of mesalazine (P = 0.006), ABCC5 (rs2293001) (P < 0.001), ITPA (rs2236206 and rs8362) (P = 0.010 and P = 0.003), and ABCB1 (rs2032582) (P = 0.028) were all associated with the ratio of 6-thioguanine nucleotides to azathioprine dose. ADK (rs10824095) (P = 0.004, odds ratio [OR] = 6.220), SLC29A1 (rs747199) (P = 0.016, OR = 5.681), and TYMS (rs34743033) (P = 0.045, OR = 3.846) were associated with neutropenia. ABCC1 (rs2074087) (P = 0.022, OR = 3.406), IMPDH1 (rs2278294) (P = 0.027, OR = 0.276), and IMPDH2 (rs11706052) (P = 0.034, OR = 3.639) had a significant impact on lymphopenia.

CONCLUSIONS

This study describes genetic polymorphisms in genes whose products may affect pharmacokinetics and which may predict the relative likelihood of benefit or risk from thiopurine treatment. These findings may serve as a basis for personalized thiopurine therapy in pediatric patients with inflammatory bowel disease, although our data need to be validated in further studies.

Analysis of ERCC1 and ERCC2 gene variants in osteosarcoma, colorectal and breast cancer

The Asn118Asn (rs11615) variant in the ERCC1 gene, and the Lys751Gln (rs13181) and Asp312Asn (rs1799793) variants in the ERCC2 gene have been associated with the development of varied types of cancer. The aim of the present study was to test for any association between the ERCC1 and ERCC2 gene variants and three different types of cancer in Mexican-mestizo patients. Patients and their respective controls were formed into three groups: The osteosarcoma group, with 28 patients and 97 controls; the colorectal group, with 108 patients and 119 controls; and the breast cancer group, with 71 patients and 74 controls. Genotyping was performed using TaqMan probes and quantitative polymerase chain reaction. Allele and genotype frequencies were compared using a χ² test. Only one SNP (rs1799793) was found to be associated with breast cancer. This is the first study analyzing the SNPs in ERCC1 and ERCC2 genes and the susceptibility to cancer in Mexican-mestizo patients with osteosarcoma, and colorectal and breast cancer.

Thymidylate synthase genotype-directed chemotherapy for patients with gastric and gastroesophageal junction cancers

BACKGROUND

Retrospective studies indicate associations between TSER (thymidylate synthase enhancer region) genotypes and clinical outcomes in patients receiving 5-FU based chemotherapy, but well-controlled prospective validation has been lacking.

METHODS

In this phase II study (NCT00515216 registered through ClinicalTrials.gov, http://clinicaltrials.gov/show/NCT00515216), patients with "good risk" TSER genotypes (at least one TSER*2 allele) were treated with FOLFOX chemotherapy to determine whether prospective patient selection can improve overall response rates (ORR) in patients with gastric and gastroesophageal junction (GEJ) cancers, compared with historical outcomes in unselected patients (estimated 43%).

RESULTS

The ORR in genotype-selected patients was 39.1% (9 partial responses out of 23 evaluable patients, 95% CI, 22.2 to 59.2), not achieving the primary objective of improving ORR. An encouraging disease control rate (DCR, consisting of partial responses and stable diseases) of 95.7% was noted and patients with homozygous TSER*2 genotype showed better tumor response.

CONCLUSIONS

In this first prospective, multi-institutional study in patients with gastric or GEJ cancers, selecting patients with at least one TSER*2 allele did not improve the ORR but led to an encouraging DCR. Further studies are needed to investigate the utility of selecting patients homozygous for the TSER*2 allele and additional genomic markers in improving clinical outcomes for patients with gastric and GEJ cancers.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00515216.

FOLFOX/FOLFIRI pharmacogenetics: The call for a personalized approach in colorectal cancer therapy

While 5-fluorouracil used as single agent in patients with metastatic colorectal cancer has an objective response rate around 20%, the administration of combinations of irinotecan with 5-fluorouracil/folinic acid or oxaliplatin with 5-fluorouracil/folinic acid results in significantly increased response rates and improved survival. However, the side effects of systemic therapy such as myelotoxicity, neurotoxicity or gastrointestinal toxicity may lead to life-threatening complications and have a major impact on the quality of life of the patients. Therefore, biomarkers that would be instrumental in the choice of optimal type, combination and dose of drugs for an individual patient are urgently needed. The efficacy and toxicity of anticancer drugs in tumor cells is determined by the effective concentration in tumor cells, healthy tissues and by the presence and quantity of the drug targets. Enzymes active in drug metabolism and transport represent important determinants of the therapeutic outcome. The aim of this review was to summarize published data on associations of gene and protein expression, and genetic variability of putative biomarkers with response to therapy of colorectal cancer to 5-fluorouracil/leucovorin/oxaliplatin and 5-fluorouracil/leukovorin/irinotecan regimens. Gaps in the knowledge identified by this review may aid the design of future research and clinical trials.

Clinical importance of recently discovered gene variants in colon cancer recurrence and prognosis

SUMMARY 

Colorectal cancer survival has increased over the past few years, mainly due to the advances in the metastatic setting. Nonetheless, in the adjuvant scenario, minor improvements have been made, as the tumor's anatomopathological features remain to be most important factors for predicting the risk of recurrence and the prognosis. A deeper understanding of the molecular mechanisms involved in colorectal carcinogenesis, progression, invasion and metastasis development, have laid the groundwork for the search of genetic biomarkers that can help identify patients at a higher risk of recurrence. Common germline variants in genes within molecular pathways responsible for cancer development and progression have proven to influence the probability of relapse and the patient's prognosis. Here, we systematically review the relevance of genetic variants as prognostic biomarkers in colorectal carcinoma.

Association of ERCC1 and ERCC2 polymorphisms with colorectal cancer risk in a Chinese population

The ERCC1 and ERCC2 genes are important in repairing DNA damage and genomic instability, and are involved in the nucleotide excision repair pathway. We hypothesized that single nucleotide polymorphisms (SNPs) in ERCC1 and ERCC2 are associated with the risk of colorectal cancer in a Chinese population. To test this hypothesis, we genotyped four functional SNPs (ERCC1 Asn118Asn, C8092A, ERCC2 Asp312Asn, and Lys751Gln) in a case-control study with 213 colorectal cancer cases and 240 cancer-free controls. We found that the ERCC1 C8092A polymorphism AA and CA/AA variant genotypes were associated with a significantly increased risk of colorectal cancer, compared with the CC genotype (OR = 2.50, 95% CI = 1.10-5.70 for AA versus CC, and OR = 1.58, 95% CI = 1.08-2.30 for CA/AA versus CC). Furthermore, the effect appeared to be more prominent among men, smokers, drinkers, and patients with rectal cancer. However, no other SNPs were observed for any significant association with colorectal cancer risk. These results suggest that the ERCC1 C8092A polymorphism may contribute to colorectal cancer susceptibility in the Chinese population. Further large and functional studies are needed to confirm our findings.

The prognostic significance of APC gene mutation and miR-21 expression in advanced-stage colorectal cancer

AIM

Colorectal cancer (CRC) is the second commonest cause of cancer death in Taiwan. Although numerous genes have been associated with tumorigenesis in colorectal cancer, only a few have been validated and used as biomarkers for predicting clinical outcome. The aim of this study was to analyse the association of APC gene mutation and miR-21 expression with clinical outcome in CRC patients.

METHOD

In total, 195 colorectal cancer patients were enrolled in a single medical centre between 2003 and 2007. APC gene mutation and expression of APC and miR-21 were analysed by direct DNA sequencing and real-time reverse transcription polymerase chain reaction. The primary outcome included 5-year overall survival and univariate (Kaplan-Meier) and multivariate (Cox regression) analyses of prognostic factors.

RESULTS

The results showed that 66 (33.8%) of 195 tumour tissues contained an APC mutation. The predominant APC gene variations were deletion mutations (50.0%). APC gene expression was low in CRC and negatively correlated with miR-21 expression and gene mutation. In advanced-stage cancer, patients with APC mutation/high miR-21 had poorer overall survival rates than those with APC mutation/low miR-21, APC wild-type/high miR-21 and APC wild-type/low miR-21.

CONCLUSION

In Taiwan, downregulation of the APC gene in CRC correlated with gene mutation and miR-21 upregulation. APC mutation and miR-21 expression could be used to predict the clinical outcome of CRC, especially in patients with advanced disease.

Predictive value of ERCC1, ERCC2, and XRCC1 overexpression for stage III colorectal cancer patients receiving FOLFOX-4 adjuvant chemotherapy

OBJECTIVES

To determine the correlation between expression of three DNA repair genes and early failure/clinical outcome of stage III colorectal cancer (CRC) patients administrated with FOLFOX-4, including the excision repair cross-complementation group 1 (ERCC1), the excision repair cross-complementing 2 (ERCC2), and X-ray repair cross-complementing protein 1 (XRCC1).

MATERIALS AND METHODS

We retrospectively analyzed clinicopathological features and ERCC1, ERCC2, XRCC1 expressions by immunohistochemical staining in 180 stage III CRC patients undergoing curative resection and treated with FOLFOX-4 chemotherapy to identify predictors of postoperative early failure.

RESULTS

Among 180 CRC patients, 44 patients were classified into early failure group, and 136 patients were categorized into non-early failure group. A multivariate logistic regression analysis showed that ERCC1 overexpression (P = 0.005), and high postoperative carcinoembryonic antigen (CEA) levels (P = 0.001) were independent predictors of early failure. Additionally, ERCC1 overexpression was not only a predictor of early failure but also for disease-free survival (P < 0.001) and overall survival (P < 0.001). However, no predictive roles of ERCC2 and XRCC1 expression among these analyzed patients.

CONCLUSIONS

ERCC1 overexpression is an important predictor of early failure in patients with stage III CRC administrating FOLFOX-4 adjuvant chemotherapy and this marker may help identify patients who would benefit from intensive follow-up and enhance therapeutic programs.

Effect of genetic polymorphisms on therapeutic response and clinical outcomes in pancreatic cancer patients treated with gemcitabine

AIM

Gemcitabine is the first chemotherapeutic agent to show clinical benefits in pancreatic cancer patients. While interindividual variability in chemoresponse is observed, genetic factors that affect drug metabolism have not been clearly defined. The purpose of this study is to evaluate the relationships between genetic polymorphisms and therapeutic efficacy in pancreatic cancer patients treated with gemcitabine.

PATIENTS & METHODS

The study population consisted of 102 pancreatic cancer patients who had been treated with a gemcitabine-based chemotherapeutic regimen. 102 genetic polymorphisms were selected from 23 genes involved in the metabolism and action sites of gemcitabine and screened for polymorphisms using the MassARRAY(®) system. The polymorphisms and haplotypes were analyzed in relation to overall survival (OS), time-to-progression (TTP) and disease progression.

RESULTS

CMPK1 360C>T was significantly associated with OS, TTP and disease progression (p = 0.042, 0.007 and 0.040, respectively, in a dominant genetic model). Additionally, CMPK1 240G>T was correlated with OS and TTP. The frequencies of the haplotypes for the CMPK1, SLC28A1, DCTD and TLE4 genes differed according to disease progression.

CONCLUSION

Genetic polymorphisms in genes related to metabolism and action sites of gemcitabine showed associations with the therapeutic efficacy, in terms of OS, TTP and disease progression in pancreatic cancer patients treated with gemcitabine-based chemotherapy. In particular, polymorphisms of the CMPK1 gene seem to provide important prognostic information.

Polymorphisms in XPD and ERCC1 Associated with Colorectal Cancer Outcome

Using the comprehensive approach to selecting polymorphisms to date, we sought to examine whether recurrence in colorectal cancer was associated with inherited variation in three genes involved in DNA repair and cell proliferation. Three polymorphisms, which are excision repair cross-complementation 1 (ERCC1), xeroderma pigmentosum group D (XPD) and epidermal growth factor receptor (EGFR), were assessed in 257 postoperative stage II/III CRC patients with 5-fluorouracial chemotherapy in Taiwan. In addition, the correlations between genetic polymorphisms and patients’ clinicopathological features were investigated. Genotypes of XPD codon751 A/A and ERCC1 codon118 T/T were associated with regional recurrence in a statistically significant way (p = 0.018). Patients who carried XPD AA and ERCC1 TT genotypes demonstrated a significantly greater regional recurrence risk (OR = 5.625, 95% CI, 1.557–20.32). Inherited variation in XPD and ERCC1 was associated with outcome in patients with colorectal cancer in Taiwan. As the significant association of single-nucleotide polymorphisms has not been studied previously in colorectal cancer, these findings suggest novel sites of variation, in part explaining the range of treatment responses seen in this disease.

Pharmacogenetic analysis of pediatric patients with acute lymphoblastic leukemia: a possible association between survival rate and ITPA polymorphism

Genetic polymorphisms are important factors in the effects and toxicity of chemotherapeutics. To analyze the pharmacogenetic and ethnic differences in chemotherapeutics, major genes implicated in the treatment of acute lymphoblastic leukemia (ALL) were analyzed. Eighteen loci of 16 genes in 100 patients with ALL were analyzed. The distribution of variant alleles were CYP3A4*1B (0%), CYP3A5*3 (0%), GSTM1 (21%), GSTP1 (21%), GSTT1 (16%), MDR1 exon 21 (77%), MDR1 exon 26 (61%), MTHFR 677 (63%), MTHFR 1298 (29%), NR3C1 1088 (0%), RFC1 80 (68%), TPMT combined genotype (7%), VDR intron 8 (11%), VDR FokI (83%), TYMS enhancer repeat (22%) and ITPA 94 (30%). The frequencies of single nucleotide polymorphisms (SNPs) of 10 loci were statistically different from those in Western Caucasians. Dose percents (actual/planned dose) or toxicity of mercaptopurine and methotrexate were not related to any SNPs. Event free survival (EFS) rate was lower in ITPA variants, and ITPA 94 AC/AA variant genotypes were the only independent risk factor for lower EFS in multivariate analysis, which was a different pharmacogenetic implication from Western studies. This study is the first pharmacogenetic study in Korean pediatric ALL. Our result suggests that there are other possible pharmacogenetic factors besides TPMT or ITPA polymorphisms which influence the metabolism of mercaptopurine in Asian populations.

Functional polymorphisms of folate metabolism and response to chemotherapy for colorectal cancer, a systematic review and meta-analysis

OBJECTIVES

Many primary studies have considered the association of polymorphisms of folate metabolism and response to 5-fluorouracil (5-FU) and capecitabine in patients with colorectal cancer. The conclusions from these studies have been conflicting and few have considered large cohorts of patients. Therefore, we have completed a systematic review and meta-analyses to summarize some of the findings to date. We conducted searches for any studies that had addressed the prognostic value of genotype analysis of thymidylate synthetase (TYMS), Methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR).

METHODS

We collected data on the study designs, and completed meta-analyses to pool congruent data about treatment effect. A narrative summary is presented for 39 studies that describe three TYMS genotypes and two MTHFR genotypes associated with response to 5-FU-based chemotherapy.

RESULTS

Data were synthesized from up to 2402 patients for the most commonly studied markers TYMS 5' UTR repeat polymorphism (rs45445694) and MTHFR 677 C>T (rs1801133). We found that the TYMS genotype associated with the lowest protein expression (2R/2R) was significantly associated with improved clinical benefit; the pooled risk ratio was relative risk=1.36 [1.11, 1.65]; P=0.003. Moreover, the same trend was observed for adverse effects; the pooled risk ratio was 2.04 [1.42, 2.95]; P=0.0001.

CONCLUSION

There is a small but statistically significant association between treatment effect (both intended effects and adverse events) and a TYMS genotype associated with low protein expression; however, the effect size is small and therefore indicates limited clinical utility.

Pharmacogenetics of oxaliplatin as adjuvant treatment in colon carcinoma: are single nucleotide polymorphisms in GSTP1, ERCC1, and ERCC2 good predictive markers?

PURPOSE

Adjuvant chemotherapy improves survival in stage III colon cancer patients. However, a subgroup of patients still develops recurrent disease at some point in time, partly because of the ineffectiveness of the chemotherapy. Predictive markers of response are therefore crucial. Our aim was to study the predictive value of functional polymorphisms in genes involved in the metabolism of oxaliplatin and in DNA repair in stage III colon cancer patients.

MATERIALS AND METHODS

Normal DNA was isolated from 98 patients diagnosed with stage III colon carcinoma. Single nucleotide polymorphisms (SNPs) in three genes (the excision repair cross-complementing genes ERCC1 [19007T>C] and ERCC2 [2251A>C], and the glutathione S-transferase pi 1 gene [GSTP1 313A>G]) were tested by PCR followed by digestion with restriction enzymes or by direct sequencing. These genes and SNPs were selected on the basis of their reported associations with oxaliplatin response in colorectal cancer.

RESULTS

The genotype frequencies were in Hardy-Weinberg equilibrium. GSTP1 and ERCC2 polymorphisms were significantly associated with sex. The AA genotype of GSTP1 313A>G was more frequent in men than in women (59% vs 30%, p = 0.02), and the CC genotype of ERCC2 2251A>C was significantly more frequent in women than in men (24% vs 6%, p = 0.02). In univariate and multivariate survival analysis, none of the tested polymorphisms seemed to influence disease-free survival. The GSTP1 AA genotype had different effects on survival between men and women; homozygous A men had significantly worse cancer-specific survival and overall survival than women with the same genotype (log rank p = 0.029 and p = 0.015, respectively).

CONCLUSION

None of the tested polymorphisms is likely to be a reliable marker of response to oxaliplatin therapy. The GSTP1 313A>G homozygous A genotype may have a prognostic value in male patients.

Pharmacogenetics of oxaliplatin as adjuvant treatment in colon carcinoma: are single nucleotide polymorphisms in GSTP1, ERCC1, and ERCC2 good predictive markers?

PURPOSE

Adjuvant chemotherapy improves survival in stage III colon cancer patients. However, a subgroup of patients still develops recurrent disease at some point in time, partly because of the ineffectiveness of the chemotherapy. Predictive markers of response are therefore crucial. Our aim was to study the predictive value of functional polymorphisms in genes involved in the metabolism of oxaliplatin and in DNA repair in stage III colon cancer patients.

MATERIALS AND METHODS

Normal DNA was isolated from 98 patients diagnosed with stage III colon carcinoma. Single nucleotide polymorphisms (SNPs) in three genes (the excision repair cross-complementing genes ERCC1 [19007T>C] and ERCC2 [2251A>C], and the glutathione S-transferase pi 1 gene [GSTP1 313A>G]) were tested by PCR followed by digestion with restriction enzymes or by direct sequencing. These genes and SNPs were selected on the basis of their reported associations with oxaliplatin response in colorectal cancer.

RESULTS

The genotype frequencies were in Hardy-Weinberg equilibrium. GSTP1 and ERCC2 polymorphisms were significantly associated with sex. The AA genotype of GSTP1 313A>G was more frequent in men than in women (59% vs 30%, p = 0.02), and the CC genotype of ERCC2 2251A>C was significantly more frequent in women than in men (24% vs 6%, p = 0.02). In univariate and multivariate survival analysis, none of the tested polymorphisms seemed to influence disease-free survival. The GSTP1 AA genotype had different effects on survival between men and women; homozygous A men had significantly worse cancer-specific survival and overall survival than women with the same genotype (log rank p = 0.029 and p = 0.015, respectively).

CONCLUSION

None of the tested polymorphisms is likely to be a reliable marker of response to oxaliplatin therapy. The GSTP1 313A>G homozygous A genotype may have a prognostic value in male patients.

APEX microarray panel for genotyping polymorphisms in cancer chemotherapy and estimation frequencies in a Slovak population

Aim: Many studies focus on monitoring response to chemotherapy, adverse effects and prediction of therapeutic effects, which depend on individual gene variability. The amount of various polymorphisms in genes involved in the folate cycle, and other metabolic pathways involved in the metabolism of chemotherapeutic drugs, are an essential topic of such studies. This work focuses on the design and establishment of a pharmacogenetically relevant panel, which could be applied to the rapid genotyping of patients treated with thiopurines, 5-fluorouracil, methotrexate, irinotecan and glucocorticoids. Materials & methods: A total of 97 variations in 36 genes associated with side effects of chemotherapeutic treatment were selected. Of these, 94 SNPs were genotyped by the arrayed primer extension (APEX; Asper Biotech Ltd) microarray method or direct sequencing. Variations of tandem repeats or gene deletions were genotyped by capillary electrophoresis and PCR detection. A total of 300 DNA samples from healthy volunteers were tested to estimate genotype frequencies for a Slovak population. All data were checked for Hardy–Weinberg equilibrium and genetic linkage between variations. Results: We designed an APEX microarray for genotyping pharmacologically relevant polymorphisms in patients undergoing chemotherapy. We estimated genotype frequencies for all 97 polymorphisms testing 300 individuals from the Slovak population, which may also serve as an estimate of central European frequencies. These data also allowed for the testing of genetic linkage between loci. Many of the determined genotype frequencies in this study were in similar ranges found in other European populations but four SNPs, rs11760837 (p = 0.018), rs1801265 (p = 0.0375), rs1801394 (p = 0.0066) and rs182455 (p = 0.0083), demonstrated stronger deviation. Conclusion: Genetic variability in genes involved in metabolic pathways of chemotherapeutic drugs, such as methotrexate, 5-fluorouracil, thiopurines or irinotecan, is responsible for individual therapy response and development of side effects. A comprehensive approach in genotyping of numerous variants is aimed to improve individual access to patients and the selection of appropriate drugs for treatment. The APEX microarray method is a valuable tool for fast, reliable and cost-effective genotyping of variants which can be used for the typing of known variants in patients prior to treatment as well as in studies searching for new genotype–phenotype associations. The opportunity of adding additional variants during the study makes the APEX microarray technology flexible and suitable for such trials.

Original submitted 4 October 2010; Revision submitted 23 November 2010.

Translational medicine and reliability of single-nucleotide polymorphism studies: can we believe in SNP reports or not?

BACKGROUND

The number of genetic association studies is increasing exponentially. Nonetheless, genetic association reports are prone to potential biases which may influence the reported outcome.

AIM

We hypothesized that positive outcome for a determined polymorphism might be over-reported across genetic association studies analysing a small number of polymorphisms, when compared to studies analysing the same polymorphism together with a high number of other polymorphisms.

METHODS

We systematically reviewed published reports on the association of glutathione s-transferase (GST) single-nucleotide polymorphisms (SNPs) and cancer outcome.

RESULT

We identified 79 eligible trials. Most of the studies examined the GSTM1, theGSTP1 Ile105Val mutation, and GSTT1polymorphisms (n = 54, 57 and 46, respectively). Studies analysing one to three polymorphisms (n = 39) were significantly more likely to present positive outcomes, compared to studies examining more than 3 polymorphisms (n=40) p = 0.004; this was particularly evident for studies analysing the GSTM1polymorphism (p =0.001). We found no significant associations between journal impact factor, number of citations, and probability of publishing positive studies or studies with 1-3 polymorphisms examined.

CONCLUSIONS

We propose a new subtype of publication bias in genetic association studies. Positive results for genetic association studies analysing a small number of polymorphisms (n = 1-3) should be evaluated extremely cautiously, because a very large number of such studies are inconclusive and statistically under-powered. Indeed, publication of misleading reports may affect harmfully medical decision-making and use of resources, both in clinical and pharmacological development setting.

ABCB1 gene polymorphisms are associated with adverse reactions in fluoropyrimidine-treated colorectal cancer patients

Aim: To find out whether SNPs in the transporter gene ATP-binding casette B1 (ABCB1) were related to adverse effects in colorectal cancer patients treated with 5-fluorouracil (5-FU) or capecitabine. Materials & methods: Patients treated with a 5-FU-based therapy (n = 67) or a capecitabine-based therapy (n = 74) were recruited and genotyped for the ABCB1 SNPs rs1128503 (C1236T), rs2032592 (G2677T/A) and rs1045642 (C3435T). Clinical data and adverse reactions were recorded. ABCB1 genotypes of patients were statistically analyzed for association with the most frequent adverse reactions. Results: Statistical associations were observed, suggesting a lower risk of neutropenia (p = 0.013) and hand–foot syndrome (HFS; p = 0.027) for the carriers of T variation for rs1128503 in capecitabine-treated patients, carriers of T variation for rs1045642 treated with capecitabine had a lower risk of HFS (p = 0.033), while those treated with 5-FU had a higher risk of diarrhea (p = 0.035), and carriers of T variation for rs2032592 treated with capecitabine were at less risk of developing HFS (p = 0.033). Conclusion: This is the first time evidence has been found of differing pharmacogenetic markers for capecitabine and 5-FU treatments. Genotyping of SNPs in the ABCB1 gene prior to chemotherapy administration could help reduce adverse reactions in colorectal cancer patients.

S100B protein expressions as an independent predictor of early relapse in UICC stages II and III colon cancer patients after curative resection

BACKGROUND

S100 calcium-binding proteins such as S100B are elevated in primary malignant melanoma and are used as tumor markers for malignant melanoma and numerous other cancers. The purpose of this study was to identify the novel predictors of early relapse in UICC stages II and III colon cancer patients and thus to identify a subgroup of patients who are at high risk for postoperative early relapse.

METHODS

Clinicopathological factors and S100B expression by immunohistochemical staining were retrospectively analyzed in 357 postoperative UICC stages II and III colon cancer patients to determine the predictors of early relapse.

RESULTS

Of 357 patients, 114 patients developed postoperative relapse during the follow-up period. Among 114 relapsed colon cancer patients, postoperative early relapse and non-early relapse were found in 56 patients (49.1%) and 58 patients (50.9%), respectively. Multivariate Cox proportional hazards analysis revealed that the presence of vascular invasion (P = .025; hazard ratio [HR], 5.532; 95% confidence interval [95% CI], 1.985-14.729), high postoperative CEA levels (P = .019; HR, 6.845; 95% CI, 2.393-15.256), and S100B overexpression (P < .001; HR, 26.250; 95% CI, 7.463-96.804) were demonstrated to be independent predictors of postoperative early relapse. Furthermore, postoperative relapsed colon cancer patients with S100B overexpression were demonstrated to have significantly lower overall survival rates than those without S100B overexpression (P < .001).

CONCLUSIONS

This study suggests that S100B protein expression is a crucial predictor of early relapse in UICC stages II and III postoperative colon cancer patients and thus could help to define patients with this tumor entity who would benefit from enhanced follow-up and therapeutic program(s).

Predictive diagnostics in colorectal cancer: impact of genetic polymorphisms on individual outcomes and treatment with fluoropyrimidine-based chemotherapy

The 5-fluorouracil (5-FU)-based chemotherapy is a standard treatment for patients with colorectal cancer. However, a relevant number of patients suffer from severe toxic side effects, such as haemotoxicity, while lacking clinical response to adjuvant therapy. The inter-individual variations of drug toxicity and efficacy of the pyrimidine antagonist observed in clinical practice are mainly determined by genetic polymorphisms. The screening of genotypes, such as thymidylate synthase, dihydropyrimidine dehydrogenase, methylene tetrahydrofolate reductase, orotate phosphoribosyltransferase or glutathione S-transferase, could help identifying those patients with colorectal carcinoma who can actually benefit from a 5-FU-based therapy. The current chapter elucidates the roles of the polymorphisms in the enzymes involved in the 5-FU metabolic pathway as prognostic and predictive markers. It reports on the relationship between various genotypes in patients with colorectal carcinoma and their responsiveness to a 5-FU-based chemotherapy, and concludes with an outlook on possible future directions in treatment of colorectal cancer.

MTHFR gene polymorphisms and response to chemotherapy in colorectal cancer: a meta-analysis

AIMS

Pharmacogenetic studies investigating the relationship between MTHFR gene polymorphisms and response to fluorouracil-based chemotherapy in patients with colorectal cancer have produced inconclusive results. In an attempt to interpret these results, a meta-analysis of all eligible studies published up until January 2009 was carried out.

MATERIALS & METHODS

A total of ten studies relating MTHFR C677T and six studies relating MTHFR A1298C to the response to chemotherapy in patients with colorectal cancer were included in the meta-analysis and random effects pooled odds ratios were estimated. The heterogeneity between studies, the sources of potential bias and the consistency of genetic effects across ethnicities were explored. Cumulative and recursive cumulative meta-analyses were also performed.

RESULTS

For both the C677T and A1298C polymorphisms, the main analysis revealed nonsignificant heterogeneity and a lack of association under the allele contrast, the recessive and dominant models. The subgroup analysis by ethnicity did not change this pattern of results. The lack of stability of the relative change of odds ratio in the recursive cumulative meta-analysis for both polymorphisms indicated the need for more evidence to support a definite lack of association. There was no differential magnitude of the effect in large versus small studies.

CONCLUSION

The available evidence indicates that MTHFR C677T and A1298C gene polymorphisms cannot be considered as reliable predictors of response to fluorouracil-based chemotherapy in patients with colorectal cancer.

Predictive factors of early relapse in UICC stage I-III colorectal cancer patients after curative resection

BACKGROUND AND OBJECTIVES

To predict the clinicopathologic factors for early relapse of UICC stage I-III colorectal cancer (CRC) patients undergoing curative resection and thus to identify a subgroup of patients who are at high risk for postoperative early relapse.

METHODS

Between January 2001 and June 2007, a total of 778 UICC stage I-III CRC patients who underwent a radical resection and regular follow-up were retrospectively analyzed. Of these 778 CRC patients, 521 colon cancer and 257 rectal cancer cases were analyzed, respectively, to determine the predictors of early relapse postoperatively. These 778 patients were followed-up intensively, and their outcomes were investigated retrospectively.

RESULTS

Out of 521 colon cancer patients, postoperative relapse after primary resection was found in 142 (27.3%) patients, and 77 (54.2%) of 142 recurrent colon cancer patients were classified as postoperative early relapse. Meanwhile, among 257 rectal cancer patients, postoperative relapse was found in 68 (26.5%) patients and 44 (64.7%) of 68 recurrent rectal cancer patients were identified as postoperative early relapse. Forty-nine (63.6%) of 77 early relapsed colon cancer patients were stage III, and likewise, 26 (59.1%) of 44 early relapsed rectal cancer patients were stage III. Univariately, postoperative early relapse of colon cancer patients was significantly correlated with the presence of vascular invasion (P < 0.001), perineural invasion (P < 0.001), high postoperative carcinoembryonic antigen (CEA) level (P = 0.001), and type of surgery (P = 0.016). Using a Cox proportional hazards analysis, the presence of vascular invasion (P = 0.033), perineural invasion (P = 0.005), and high postoperative CEA levels (P = 0.001) were demonstrated to be independent predictors of postoperative early relapse of colon cancer patients, while in rectal cancer patients, both vascular invasion (P = 0.039) and perineural invasion (P = 0.008) were statistically significant predictors of early relapse by univariate analysis. Using a Cox proportional hazards analysis, only perineural invasion (P = 0.043) was an independent factor. Early relapse cases had significant lower overall survival rates than non-early relapse cases either in colon cancer (P < 0.001) or in rectal cancer (P = 0.0091) patients.

CONCLUSIONS

This study suggests that vascular invasion, perineural invasion, and postoperative CEA level may be significant factors for postoperative early relapse of colon cancer; while only perineural invasion is considered to be a significant predictor in rectal cancer patients. Identification of these high-risk UICC stage I-III CRC patients of early relapse is important, and thus could help to define patients with this tumor entity for an enhanced follow-up and therapeutic program.

Rapid diagnosis of tuberculosis directly from clinical specimens using a gene chip

The aim of this study was to explore a gene chip capable of detecting the presence of Mycobacterium tuberculosis isolates directly in clinical sputum specimens and to compare it with current molecular detection techniques. At first, we selected 13 M. tuberculosis-specific target genes to construct a gene chip for rapid diagnosis. Using the membrane array method, we diagnosed M. tuberculosis by gene chip directly from 246 sputum specimens from patients suspected of having tuberculosis. Among 80 M. tuberculosis complex (MTBC) culture-positive sputum specimens, the MTBC detection rate was 62.5% (50/80) by PCR-restriction fragment length polymorphism (RFLP), 70% (56/80) by acid-fast staining, and 85% (68/80) by the membrane array method. Furthermore, subspecies showed different gene expression patterns in the membrane array. In conclusion, MTBC could be detected directly in sputum by the membrane array method. The rapidity of detection and the capability of differentiating subspecies could make this method useful in the control and prevention of tuberculosis.

Survival of distinct Asian groups among colorectal cancer cases in California

BACKGROUND

It has been reported that Asian ethnicity confers a survival benefit in colorectal cancer (CRC) compared with other ethnicities, but it is not known if this is limited to specific Asian subsets. In the current study, the authors attempted to determine differences using data from the large, population-based California Cancer Registry (CCR).

METHODS

The authors conducted a case-only analysis of CCR data (1994-2003), including descriptive analysis of relevant clinical variables. Overall survival univariate analyses were conducted using the Kaplan-Meier method. Multivariate survival analyses were performed using Cox proportional hazards ratios (HR).

RESULTS

The 61,494 incident cases of colon and 24,350 incident cases of rectal cancer analyzed included 1905 Chinese, 1162 Filipino, 414 Vietnamese, 391 Korean, 1091 Japanese, 148 Asian Indian, and 77,554 Caucasians. After adjustment for age, sex, grade, histology, site within the colon, stage of disease, insurance status, socioeconomic status (SES), and therapy, Filipino (colon: HR, 0.85; 95% confidence interval [95% CI], 0.76-0.95) (rectum: HR, 0.82; 95% CI, 0.71-0.94) and Chinese ethnicity (colon: HR, 0.90; 95% CI, 0.92-0.98) had significantly decreased risk of death compared with Caucasians. Sigmoid lesions were independently associated with improved survival among all cases (HR, 0.92; 95% CI, 0.88-0.95) (referent group were proximal and transverse lesions), and among Asian-only cases in separate analysis (HR, 0.78; 95% CI, 0.70-0.87).

CONCLUSIONS

Although survival after CRC diagnosis is improved for Asians in general, significant survival differences are observed only in specific Asian subsets. Data from the current study suggest that survival among Asians is less affected by SES or treatment disparities, and may be because of biologic factors.