Impact of genomic alterations on lapatinib treatment outcome and cell-free genomic landscape during HER2 therapy in HER2+ gastric cancer patients.

Background: To identify predictive markers for responders in lapatinib-treated patients and to demonstrate molecular changes during lapatinib treatment via cell-free genomics. Patients and methods: We prospectively evaluated the efficacy of combining lapatinib with capecitabine and oxaliplatin as first line neoadjuvant therapy in patients with previously untreated, HER2-overexpressing advanced gastric cancer. A parallel biomarker study was conducted by simultaneously performing immunohistochemistry and next-generation sequencing (NGS) with tumor and blood samples. Results: Complete response was confirmed in 7/32 patients (21.8%), 2 of whom received radical surgery with pathologic-confirmed complete response. Fifteen partial responses (46.8%) were observed, resulting in a 68.6% overall response rate. NGS of the 16 tumor specimens demonstrated that the most common co-occurring copy number alteration was CCNE1 amplification, which was present in 40% of HER2+ tumors. The relationship between CCNE1 amplification and lack of response to HER2-targeted therapy trended toward statistical significance (66.7% of non-responders versus 22.2% of responders harbored CCNE1 amplification; P = 0.08). Patients with high level ERBB2 amplification by NGS were more likely to respond to therapy, compared with patients with low level ERBB2 amplification (P = 0.02). Analysis of cfDNA showed that detectable ERBB2 copy number amplification in plasma was predictive to the response (100%, response rate) and changes in plasma-detected genomic alterations were associated with lapatinib sensitivity and/or resistance. The follow-up cfDNA genomics at disease progression demonstrated that there are emergences of other genomic aberrations such as MYC, EGFR, FGFR2 and MET amplifications. Conclusions: The present study showed that HER2+ GC patients respond differently according to concomitant genomic aberrations beyond ERBB2, high ERBB2 amplification by NGS or cfDNA can be a positive predictor for patient selection, and tumor genomic alterations change significantly during targeted agent therapy.

Emergence of CTNNB1 mutation at acquired resistance to KIT inhibitor in metastatic melanoma.

PURPOSE: The KIT inhibitor, imatinib, has shown promising efficacy in patients with KIT-mutated melanoma; however, acquisition of resistance to imatinib occurs rapidly in the majority of patients. The mechanisms of acquired resistance to imatinib in melanoma remain unclear. METHODS: We analyzed biopsy samples from paired baseline and post-treatment tumor lesions in one patient with KIT-mutated melanoma who had had an initial objective tumor regression in response to imatinib treatment followed by disease progression 8 months later. RESULTS: Targeted deep sequencing from post-treatment biopsy samples detected an additional mutation in CTNNB1 (S33C) with original KIT L576P mutation. We examined the functional role of the additional CTNNB1 S33C mutation in resistance to imatinib indirectly using the Ba/F3 cell model. Ba/F3 cell lines transfected with both the L576P KIT mutation and the CTNNB1 S33C mutation demonstrated no growth inhibition despite imatinib treatment, whereas growth inhibition was observed in the Ba/F3 cell line transfected with the L576 KIT mutation alone. CONCLUSIONS: We report the first identification of the emergence of a CTNNB1 mutation that can confer acquired resistance to imatinib. Further investigation into the causes of acquired resistance to imatinib will be essential to improve the prognosis for patients with KIT-mutated melanoma.

Vascular Structures of the Right Colon: Incidence and Variations with Their Clinical Implications.

BACKGROUND AND AIMS: There is a demand for a better understanding of the vascular structures around the right colonic area. Although right hemicolectomy with the recent concept of meticulous lymph node dissection is a standardized procedure for malignant diseases among most surgeons, variations in the actual anatomical vascular are not well understood. The aim of the present review was to present a detailed overview of the vascular variation pertinent to the surgery for right colon cancer. MATERIALS AND METHODS: Medical literature was searched for the articles highlighting the vascular variation relevant to the right colon cancer surgery. RESULTS: Recently, there have been many detailed studies on applied surgical vascular anatomy based on cadaveric dissections, as well as radiological and intraoperative examinations to overcome misconceptions concerning the arterial supply and venous drainage to the right colon. Ileocolic artery and middle colic artery are consistently present in all patients arising from the superior mesenteric artery. Even though the ileocolic artery passes posterior to the superior mesenteric vein in most of the cases, in some cases courses anterior to the superior mesenteric artery. The right colic artery is inconsistently present ranging from 63% to 10% across different studies. Ileocolic vein and middle colic vein is always present, while the right colic vein is absent in 50% of patients. The gastrocolic trunk of Henle is present in 46%-100% patients across many studies with variation in the tributaries ranging from bipodal to tetrapodal. Commonly, it is found that the right colonic veins, including the right colic vein, middle colic vein, and superior right colic vein, share the confluence forming the gastrocolic trunk of Henle in a highly variable frequency and different forms. CONCLUSION: Understanding the incidence and variations of the vascular anatomy of right side colon is of crucial importance. Failure to recognize the variation during surgery can result in troublesome bleeding especially during minimal invasive surgery.

Identification of lactoferrin and glutamate receptor-interacting protein 1 in bovine cervical mucus: A putative marker for oestrous detection.

Accurate detection of oestrus is important for artificial insemination. The aim of this study was to identify oestrous-specific bovine cervical mucus proteins that could be used to determine the optimal time for artificial insemination. Non-oestrous and controlled internal drug release (CIDR)-induced oestrous-stage mucus proteins were purified and subjected to surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, sodium dodecyl sulphate polyacrylamide gel electrophoresis and MALDI-TOF/TOF. Among differentially expressed proteins, lactoferrin (LF) and glutamate receptor-interacting protein 1 (GRIP1) showed a twofold increase during the CIDR-induced oestrous stage compared to the levels in non-oestrous stage in bovine cervical mucus. The RT-PCR, Western blotting and immunohistochemistry results showed that LF and GRIP1 expression was significantly increased during the oestrous stage in the uterus. This study demonstrated that bovine LF and GRIP1 exist during the oestrous stage, but not during the non-oestrous stage, suggesting that cervical mucus LF and GRIP1 are useful oestrous detection markers in cattle.

Profiling of rectal cancers MRI in pathological complete remission states after neoadjuvant concurrent chemoradiation therapy.

AIM: To fully characterise the magnetic resonance imaging (MRI) traits of rectal cancers in a large sample of patients, each experiencing pathological complete remission (pCR) after neoadjuvant concurrent chemoradiation therapy (CCRT). MATERIALS AND METHODS: A total of 120 patients (77 male, 43 female; median age, 59.5 years; range, 32-81 years) with rectal cancers in CCRT-induced pCR states who underwent pre- and post-CCRT MRI and eventual surgery between July, 2005 and September, 2014 were retrospectively reviewed. In most (n=100), diffusion-weighted imaging was also performed. Tumour volume, tumour regression grade (TRG), T-stage, mesorectal fascia (MRF) status, and T2 signal intensity (T2-SI) were analysed. Paired t-test and McNemar's test were applied for statistical comparisons. RESULTS: Tumour volume declined sharply after CCRT (pre-CCRT, 21.5 ± 22.4 cm(3); post-CCRT, 6.6 ± 8.4 cm(3); p<0.001). TRG distribution was as follows: G1 (clinical CR), 3; G2, 38; G3, 78; G4, 1; and G5 (marked progression), 0. Downstaging of T-stage (34%,16/47) and MRF status (19.7%,13/66) did occur; but on post-CCRT MRI, 25.8% (31/120) remained at T3 ≥ 5 mm or T4 stage, and 44.2% (53/120) were MRF-positive. A majority (88.3%, 106/120) of patients displayed intermediate T2-SI prior to CCRT. Most converted to dark T2-SI after CCRT, with 12.5% (15/120) unchanged. On post-CCRT MRI, 11% (11/100) of patients showed diffusion restriction. CONCLUSION: MRI findings in CCRT-induced pCR-status rectal cancers were highly variable. Tumour volume and T2-SI mostly decreased; however, such lesions occasionally presented with unexpected atypical features, such as large residual volume and/or intermediate T2-SI.

Association between eNOS polymorphisms and risk of coronary artery disease in a Korean population: a meta-analysis.

Coronary artery disease (CAD), a multifactorial disease, is a common cause of mortality in humans. Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene (-786T>C, 4a4b, and 894G>T) have been previously associated with increased CAD risk. However, the sample size of this previous study was too small and limited to comprehensively define an association between eNOS polymorphisms and CAD; therefore, this analysis was duplicated with a larger population. The study was conducted on 559 patients with CAD and 574 healthy controls. Genetic DNA was extracted using the commercial G-DEX blood extraction kit and statistical analyses were performed on the GraphPad prism 4.0 and MedCalc 12.0 statistical software platforms. No single variant of the eNOS polymorphism was associated with CAD risk. The combination genotypes of eNOS -786TT/4a4b+4a4a [adjusted odds ratio (AOR) = 0.122; 95% confidence interval (CI): 0.042-0.358] and eNOS -786TC+CC/4b4b (AOR = 0.379; 95%CI: 0.147-0.979) were associated with decreased CAD incidence. Haplotype analysis revealed that the T-4a haplotype of eNOS -786T>C and 4a4b exerted a protective effect against CAD. The association between eNOS -786T>C and increased CAD risk was not replicated in this (larger) population. However, some combined genotypes showed a meaningful association with CAD risk.

Multicentre study of robotic intersphincteric resection for low rectal cancer.

BACKGROUND: There is a lack of information regarding the oncological safety of robotic intersphincteric resection (ISR) with coloanal anastomosis. The objective of this study was to compare the long-term feasibility of robotic compared with laparoscopic ISR. METHODS: Between January 2008 and May 2011, consecutive patients who underwent robotic or laparoscopic ISR with coloanal anastomosis from seven institutions were included. Propensity score analyses were performed to compare outcomes for groups in a 1 : 1 case-matched cohort. The primary endpoint was 3-year disease-free survival. RESULTS: A total of 334 patients underwent ISR with coloanal anastomosis, of whom 212 matched patients (106 in each group) formed the cohort for analysis. The overall rate of conversion to open surgery was 0.9 per cent in the robotic ISR group and 1.9 per cent in the laparoscopic ISR group. Nine patients (8.5 per cent) in the laparoscopic group and three (2.8 per cent) in the robotic ISR group still had a stoma at last follow-up (P = 0.075). Total mean hospital costs were significantly higher for robotic ISR (€ 12,757 versus € 9223 for laparoscopic ISR; P = 0.037). Overall 3-year local recurrence rates were similar in the two groups (6.7 per cent for robotic and 5.7 per cent for laparoscopic resection; P = 0.935). The combined 3-year disease-free survival rates were 89.6 (95 per cent c.i. 84.1 to 95.9) and 90.5 (85.4 to 96.6) per cent respectively (P = 0.298). CONCLUSION: Robotic ISR with coloanal anastomosis for rectal cancer has reasonable oncological outcomes, but is currently too expensive with no short-term advantages.

Efficacy of rhBMP-2/Hydroxyapatite on Sinus Floor Augmentation: A Multicenter, Randomized Controlled Clinical Trial.

The aim of this randomized single-blinded active-controlled clinical study was to evaluate the early efficacy of low-dose Escherichia coli-derived recombinant human bone morphogenetic protein 2 (rhBMP-2) soaked with hydroxyapatite granules (BMP-2/H) as compared with an inorganic bovine bone xenograft (ABX) in maxillary sinus floor augmentation. In a total of 127 subjects who were enrolled at 6 centers, maxillary sinus floors were augmented with 1 mg/mL of rhBMP-2 (0.5 to 2.0 mg per sinus) and BMP-2/H (0.5 to 2.0 g; n = 65) or with ABX alone (0.5 to 2.0 g; n = 62). Core biopsies were obtained 3 mo after the augmentation surgery and were analyzed histomorphometrically. The mean new bone formation with BMP-2/H and ABX augmentation was 16.10% ± 10.52% and 8.25% ± 9.47%, respectively. The BMP-2/H group was noninferior to the ABX group; the lower limit of the 1-sided 97.5% confidence interval for the difference between the 2 groups was calculated as 4.33%, which was greater than the prespecified noninferiority margin of -3.75%. An additional test with the Wilcoxon rank-sum test with a 2-sided 5% significance level showed that bone formation between the 2 groups was significantly different (P < 0.0001). The soft tissue and residual graft areas showed no significant differences between the groups. With regard to safety, no significant difference between the 2 groups was observed; there was no significant increase in the amount of rhBMP-2 antibody in the serum after BMP-2/H grafting. Our study suggested that low-dose Escherichia coli-derived rhBMP-2 with hydroxyapatite was effective in early stages for enhanced bone formation after maxillary sinus floor augmentation without harmful adverse events (Clinicaltrials.gov NCT01634308).

Comparison of miniplates and biodegradable plates in reconstruction of the mandible with a fibular free flap.

Miniplates and reconstruction plates are usually used to fix a fibular free flap, the gold standard in reconstruction of large segmental mandibular defects. Though biodegradable plates are used in orthognathic operations and repair of fractures nowadays, we know of no studies of the use of biodegradable plates in the reconstruction of segmental mandibular defects including a fibular free flap. We retrospectively reviewed 47 patients who had reconstruction of segmental mandibular defects with fibular free flaps during the past 10 years, and recorded clinical data and morbidity. We compared patients who had reconstruction of such defects with fibular free flaps and miniplates (n=26) with those in whom biodegradable plates had been used (n=21). There was no significant difference between miniplates and biodegradable plates with regard to overall complications (p=0.45) and failure of flaps (p=0.59). After confounding factors had been adjusted for with Cox's proportional hazards regression, there was no significant difference in the proportion of patients who developed a complication between the two groups (p=0.4). The type of plate does not seem to affect overall morbidity in reconstruction of the mandible with a fibular free flap.

Safe anastomosis in laparoscopic and robotic low anterior resection for rectal cancer: a narrative review and outcomes study from an expert tertiary center.

Anastomotic leak and stricture formation are recognised complications of colorectal anastomoses. Surgical technique has been implicated in its aetiology. The use of innovative anastomotic techniques and technical standardisation may facilitate risk modification. Early detection of complications using novel diagnostic tests can lead to reduction in delay of diagnosis as long as a standard system is used. We review our practice for creation a safe anastomosis for minimal invasive rectal cancer resection. Several technical points discussed and evaluated based on the evidence. We propose several recommendations aiming to standardize the technique and to minimize anastomotic complications.

Overview of anal fistula and systematic review of ligation of the intersphincteric fistula tract (LIFT).

Anal fistula management has long been a challenge for surgeons. Presently, no technique exists that is ideal for treating all types of anal fistula, whether simple or complex. A higher incidence of poor sphincter function and recurrence after surgery has encouraged the development of a new sphincter-sparing procedure, ligation of the intersphincteric fistula tract (LIFT), first described by Van der Hagen et al. in 2006. We assessed the safety, feasibility, success rate, and continence of LIFT as a sphincter-saving procedure. A literature search of articles in electronic databases published from January 2006 to August 2012 was performed. Analysis followed Preferred Reporting Items for Systematic Reviews recommendations. All LIFT-related articles published in the English language were included. We excluded case reports, abstracts, letters, non-English language articles, and comments. The procedure was described in detail as reported by Rojanasakul. Thirteen original studies, including 435 patients, were reviewed. The most common fistula procedure type was transsphincteric (92.64 %). The overall median operative time was 39 (±20.16) min. Eight authors performed LIFT as a same-day surgery, whereas the others admitted patients to the hospital, with an overall median stay of 1.25 days (range 1-5 days). Postoperative complications occurred in 1.88 % of patients. All patients remained continent postoperatively. The overall mean length of follow-up was 33.92 (±17.0) weeks. The overall mean healing rate was 81.37 (±16.35) % with an overall mean healing period of 8.15 (±5.96) weeks. Fistula recurrence occurred in 7.58 % of patients. LIFT represents a new, easy-to-learn, and inexpensive sphincter-sparing procedure that provides reasonable results. LIFT is safe and feasible, with favorable short- and long-term outcomes. However, additional prospective randomized studies are required to confirm these findings.

Association between VEGF and eNOS gene polymorphisms and lumbar disc degeneration in a young Korean population.

Disturbances in blood flow to intervertebral discs (IVD) play an important role in IVD degeneration. Vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) are extremely important angiogenic factors for vasodilation and neovascularization. We investigated the relationship between single nucleotide polymorphisms (SNPs) of the VEGF and eNOS genes and genetic susceptibility to lumbar IVD degeneration in a young adult Korean population. Two hundred and forty-one participants (aged 18 to 30 years), with or without low back pain, were selected for the study. Magnetic resonance imaging was made of the lumbar spine in all participants. The patient group (N = 102) had low back pain clinically and lumbar IVD degeneration radiographically. The control group (N = 139) included subjects with and without low back pain; all were negative radiographically for lumbar IVD degeneration. Using PCR-RFLP analysis, we analyzed VEGF (-2578C>A, -1154G>A, -634G>C, and 936C>T) and eNOS (-786T>C, 4a4b and 894G>T) SNPs. We made combined analyses of the genes and performed haplotype analyses. There were no significant differences in the genotype distribution of polymorphisms of VEGF and eNOS genes among patients and controls. However, the frequency of VEGF -2578CA +AA/-634CC combined genotypes was significantly higher in patients when compared with controls [odds ratio (OR) = 21.00; 95% confidence interval (CI) = 2.590- 170.240]. The frequencies of the -2578A/-1154A/-634C/936C (OR = 3.831; 95%CI = 1.068-13.742), -2578A/-1154A/-634C (OR = 3.356; 95%CI = 1.198-9.400), and -2578A/-634C/936C (OR = 10.820; 95%CI = 2.811-41.656) haplotypes were also significantly higher in patients than in controls. We conclude that the combined genotype VEGF -2578CA+AA/-634CC is a possible risk factor for IVD degeneration and the VEGF -2578A/-1154A/-634C/936C haplotype may increase the risk for development of IVD degeneration. Furthermore, the VEGF -634C allele appears to be associated with susceptibility to IVD degeneration.

Association of transforming growth factor-beta 1 gene polymorphism with genetic susceptibility to ossification of the posterior longitudinal ligament in Korean patients.

Ossification of the posterior longitudinal ligaments (OPLL) has been considered to be associated with abnormalities of bone metabolism, and transforming growth factor-ß1 (TGF-ß1) has been demonstrated to affect the bone remodeling process. We investigated two SNPs of the TGF-ß1 promoter (-509C>T; rs1800469) and exon 1 (869T>C; rs1982073) in 298 Koreans (98 patients with OPLL and 200 control subjects). The promoter SNP -509C>T was determined by PCR and RFLP, and the TaqMan probe assay was used to determine 869T>C polymorphism genotypes. The subjects were divided into OPLL continuous group (continuous type plus mixed type) and OPLL segmental group (segmental and localized type). We also separately analyzed this association according to gender difference. There was no significant difference in genotype distributions of -509C>T and 869T>C polymorphisms of the TGF-ß1 gene between OPLL patients and controls. A combined analysis of TGF-ß1 -509C>T and 869T>C polymorphisms showed no significant association with OPLL, and a subgroup analysis did not show any significant correlation between the SNP -509C>T or SNP 869T>C and OPLL subgroups. Stratification by gender demonstrated no significant effect. We conclude that promoter region (-509C>T) and exon 1 (869T>C) polymorphisms are not associated with OPLL in the Korean population.

Genetic Polymorphisms of the Bovine NOV Gene Are Significantly Associated with Carcass Traits in Korean Cattle.

The objective of this study was to investigate single nucleotide polymorphisms (SNPs) in the bovine nephroblastoma overexpressed (NOV) gene and to evaluate whether these polymorphisms affect carcass traits in the Korean cattle population. We resequenced to detect SNPs from 24 unrelated individuals and identified 19 SNPs within the full 8.4-kb gene, including the 1.5-kb promoter region. Of these 19 SNPs, four were selected for genotyping based on linkage disequilibrium (LD). We genotyped 429 steers to assess the associations of these four SNPs with carcass traits. Statistical analysis revealed that g.7801T>C and g.8379A>C polymorphisms in the NOV gene were associated with carcass weight (p = 0.012 and 0.008, respectively), and the g.2005A>G polymorphism was associated with the back fat thickness (BF) trait (p = 0.0001). One haplotype of the four SNPs (GGTA) was significantly associated with BF (p = 0.0005). Our findings suggest that polymorphisms in the NOV gene may be among the important genetic factors affecting carcass yield in beef cattle.

Effects of Dietary Fat Types on Growth Performance, Pork Quality, and Gene Expression in Growing-finishing Pigs.

This study was performed to determine the effects of dietary fat sources, i.e., beef tallow, soybean oil, olive oil and coconut oil (each 3% in feed), on the growth performance, meat quality and gene expression in growing-finishing pigs. A total of 72 crossbred pigs (Landrace×Large White×Duroc) were used at 71±1 kg body weight (about 130 d of age) in 24 pens (320×150 cm) in a confined pig house (three pigs per pen) with six replicate pens per treatment. The growing diet was given for periods of 14±3 d and the finishing diet was given for periods of 28±3 d. The fat type had no significant effect either on growth performance or on chemical composition or on meat quality in growing-finishing pigs. Dietary fat type affected fatty acid composition, with higher levels of unsaturated fatty acids (UFAs) and monounsaturated fatty acids (MUFAs) in the olive oil group. Microarray analysis in the Longissimus dorsi identified 6 genes, related to insulin signaling pathway, that were differentially expressed among the different feed groups. Real time-PCR was conducted on the six genes in the longissimus dorsi muscle (LM). In particular, the genes encoding the protein kinase, cAMP-dependent, regulatory, type II, alpha (PRKAR2A) and the catalytic subunit of protein phosphatase 1, beta isoform (PPP1CB) showed the highest expression level in the olive oil group (respectively, p<0.05, p<0.001). The results of this study indicate that the type of dietary fat affects fatty acid composition and insulin signaling-related gene expression in the LM of pigs.

Adenosine triphosphate-based chemotherapy response assay-guided chemotherapy in unresectable colorectal liver metastasis.

BACKGROUND: This study aims to evaluate the effectiveness of adenosine triphosphate-based chemotherapy response assay (ATP-CRA)-guided neoadjuvant chemotherapy for increasing resectability in patients with unresectable colorectal liver metastasis. PATIENTS AND METHODS: Patients were randomised into two groups: Group A was treated by conventional chemotherapy regimen and Group B was treated by chemotherapy regimen according to the ATP-CRA. Three chemotherapeutic agents (5-fluorouracil, oxaliplatin and irinotecan) were tested by ATP-CRA and more sensitive agents were selected. Either FOLFOX or FOLFIRI was administered. Between Group A and B, treatment response and resectability were compared. RESULTS: Between November 2008 and October 2010, a total 63 patients were randomised to Group A (N=32) or Group B (N=31). FOLFOX was more preferred in Group A than in Group B (26 out of 32 (81.3%) vs 20 out of 31 (64.5%)). Group B showed better treatment response than Group A (48.4% vs 21.9%, P=0.027). The resectability of hepatic lesion was higher in Group B (35.5% vs 12.5%, P=0.032). Mean duration from chemotherapy onset to the time of liver resection was 11 cycles (range 4-12) in Group A and 8 cycles (range 8-16) in Group B. CONCLUSION: This study showed that tailored-chemotherapy based on ATP-CRA could improve the treatment response and resectability in initially unresectable colorectal liver metastasis.

Transanal specimen extraction in robotic rectal cancer surgery.

BACKGROUND: The aim of this study was to identify the benefits of robotic transanal specimen extraction (RTSE) compared with minilaparotomy specimen extraction (MSE). METHODS: Patients who underwent totally robotic surgery with curative intent for treatment of adenocarcinoma of the rectum below 12 cm from the anal verge were selected from the authors' database. Patients were divided into RTSE and MSE groups according to the method of specimen delivery. Clinicopathological features and perioperative surgical outcomes were compared between the two groups. RESULTS: There were 53 patients in the RTSE group and 66 in the MSE group. No differences were observed in overall complications. Postoperative recovery was faster in the RTSE group in terms of resumption of a soft diet (mean(s.d.) 3·5(1·5) versus 4·6(1·7) days; P < 0·001) and length of hospital stay (9·0(4·8) versus 11·3(5·3) days; P = 0·016). Pain scores on a visual analogue scale were significantly lower in the RTSE group than in the MSE group from day 2 to day 5 after surgery (P = 0·021 to P < 0·001). CONCLUSION: RTSE in robotic rectal cancer surgery was associated with less pain and a faster recovery than MSE.

CYP2A6 and ERCC1 polymorphisms correlate with efficacy of S-1 plus cisplatin in metastatic gastric cancer patients.

BACKGROUND: We evaluated the association between polymorphisms of cytochrome P450 2A6 (CYP2A6)/excision repair cross-complementation group 1 (ERCC1)/X-ray repair cross-complementing group 1(XRCC1) and treatment outcomes of metastatic gastric cancer (MGC) patients treated with S-1/cisplatin. METHODS: Among MGC patients (n=108), who received S-1 (40 mg m(-2) b.i.d., days 1-14) and cisplatin (60 mg m(-2), day 1) every 3 weeks, we analysed the wild-type allele (W) and variants (V) of CYP2A6 (*4, *7, *9, *10), and the polymorphisms of ERCC1 (rs11615, rs3212986) and XRCC1 (rs25487). RESULTS: Patients having fewer CYP2A6 variants had better response rates (W/W vs W/V other than *1/*4 vs V/V or *1/*4=66.7 vs 58.3 vs 32.3%; P=0.008), time to progression (TTP) (7.2 vs 6.1 vs 3.5 months, P=0.021), and overall survival (23.2 vs 15.4 vs 12.0 months, P=0.004). ERCC1 19442C>A (rs3212986) was also associated with response rate (C/C, 46.7% vs C/A, 55.3% vs A/A, 87.5%) (P=0.048) and TTP (4.4 vs 7.6 vs 7.9 months) (P=0.012). Patients carrying both risk genotypes of CYP2A6 (V/V or 1/*4) and ERCC1 19442C>A (C/C) vs those carrying none showed an adjusted odds ratio of 0.113 (P=0.004) for response, and adjusted hazard ratios of 3.748 (P=0.0001) for TTP and 2.961 (P=0.006) for death. CONCLUSION: Polymorphisms of CYP2A6 and ERCC1 19442C>A correlated with the efficacy of S-1/cisplatin.