Establishment and Characterization of Paired Primary and Peritoneal Seeding Human Colorectal Cancer Cell Lines: Identification of Genes That Mediate Metastatic Potential.

Peritoneal metastasis is one of the major patterns of unresectability in colorectal cancer (CRC) and a cause of death in advanced CRC. Identification of distinct gene expressions between primary CRC and peritoneal seeding metastasis is to predict the metastatic potential of primary human CRC. Three pairs of primary CRC (SNU-2335A, SNU-2404A, and SNU-2414A) and corresponding peritoneal seeding (SNU-2335D, SNU-2404B, and SNU-2414B) cell lines were established to determine the different gene expressions and resulting aberrated signaling pathways in peritoneal metastasis tumor using whole exome sequencing and microarray. Whole exome sequencing detected that mutation in CYP2A7 was exclusively shared in peritoneal seeding cell lines. Microarray identified that there were five upregulated genes (CNN3, SORBS1, BST2, EPSTI1, and KLHL5) and two downregulated genes (TRY6 and STYL5) in the peritoneal metastatic cell lines. CNN3 expression was highly augmented in both mRNA and protein levels in peritoneal metastasis cells. Knockdown of Calponin 3 resulted in augmented level of E-cadherin in peritoneal metastasis cells, and migration and invasiveness decreased accordingly. We suggest that CNN3 takes part in cell projection and movement, and the detection and distribution of CNN3 may render prognostic information for predicting peritoneal seeding metastasis from primary colorectal cancer.

Clinicopathological Features and Type of Surgery for Lynch Syndrome: Changes during the Past Two Decades.

PURPOSE: The Korean Hereditary Tumor Registry, the first and one of the largest registries of hereditary tumors in Korea, has registered about 500 families with hereditary cancer syndromes. This study evaluates the temporal changes in clinicopathologic features and surgical patterns of Lynch syndrome (LS) patients. MATERIALS AND METHODS: Data on 182 unrelated LS patients were collected retrospectively. The patients were divided into the period 1 group (registered in 1990-2004) and 2 (registered in 2005-2014). The clinical characteristics of the two groups were compared to identify changes over time. RESULTS: The period 1 group included 76 patients; the period 2 group, 106 patients. The mean ages at diagnosis were 45.1 years (range, 13 to 85 years) for group 1 and 49.7 years (range, 20 to 84 years) for group 2 (p=0.015). The TNM stage at diagnosis did not differ significantly-period 1 group: stage 0-I (n=18, 23.7%), II (n=37, 48.7%), III (n=19, 25.0%), and IV (n=2, 2.6%); period 2 group: stage 0-I (n=30, 28.3%), II (n=35, 33.0%), III (n=37, 34.9%), and IV (n=4, 3.8%). Extended resection was more frequently performed (55/76, 72.4%) in the period 1 group than period 2 (49/106, 46.2%) (p=0.001). CONCLUSION: Colorectal cancer in patients with LS registered at the Korean Hereditary Tumor Registry is still diagnosed at an advanced stage, more than two decades after registry's establishment. Segmental resection was more frequently performed in the past decade. A prompt nationwide effort to raise public awareness of hereditary colorectal cancer and to support hereditary cancer registries is required in Korea.

Effect of Visceral Obesity on Surgical Outcomes of Patients Undergoing Laparoscopic Colorectal Surgery.

BACKGROUND: Visceral obesity has been known to be more pathogenic than body mass index (BMI). There have been a few reports about the association between visceral obesity and surgical outcomes in laparoscopic surgery. The aim of this study was to evaluate the effect of visceral obesity on surgical outcomes undergoing laparoscopic colorectal surgery. METHODS: Between January 2005 and December 2012, a total of 543 patients who underwent laparoscopic resection for colorectal cancer and had available computed tomography (CT) scans were included in this retrospective study. Visceral fat volumes (VFVs) were measured in preoperative CT scans from S1 to 12.5 cm above. Patients were divided into an obese group and a non-obese group according to VFV and BMI. Obesity was defined by VFV ≥1.92 dm(3) (75% value of VFV) or BMI ≥25 kg/m(2). RESULTS: There were 136 (25.0%) and 150 (27.6%) obese patients according to VFV and BMI, respectively. The high VFV group had a longer operative times (165.2 ± 84.4 vs. 146.1 ± 58.9 min; P = 0.016), higher blood loss during surgery (132.5 ± 144.8 vs. 98.3 ± 109.6 ml; P = 0.012), more frequent conversion to laparotomy (5.9 vs. 1.5%; P = 0.010), and more frequent major complications (Dindo score ≥3; 11.0 vs. 4.7%; P = 0.008), whereas there was no significant difference between the high and low BMI groups. High VFV was a significant independent risk factor for open conversion (odds ratio 4.964, 95% confidence interval 1.336-18.438, P = 0.017). CONCLUSIONS: Visceral obesity can be a more clinically useful predictor than BMI in predicting surgical outcomes for laparoscopic colorectal cancer surgery.

Survival paradox between stage IIB/C (T4N0) and stage IIIA (T1-2N1) colon cancer.

BACKGROUND: The survival paradox between stage IIB/C (T4N0) and stage IIIA (T1-2N1) colon cancer remains in the 7th edition of the American Joint Committee on Cancer staging system. This multicenter study aimed to compare the oncologic outcomes of T4N0 and T1-2N1 colon cancers and to investigate the presumptive prognostic factors that might influence the survival paradox. METHODS: Patients who underwent curative surgery for pT4N0 (n = 224) and pT1-2N1 (n = 135) primary colon cancer between January 1999 and December 2010 at five tertiary referral cancer centers were included for analysis. The clinicopathologic, treatment-related factors, and oncologic outcomes in terms of the 5-year overall survival (5-OS) and 5-year disease-free survival (5-DFS) were compared. RESULTS: The T4N0 group had significantly worse 5-OS and 5-DFS rates than the T1-2N1 group (5-OS: 84.0 vs. 92.3 %, p = 0.012; 5-DFS: 73.6 vs. 88.0 %, p = 0.001). T4N0 cancers more frequently showed elevated preoperative carcinoembryonic antigen, lower grade of differentiation, larger tumor size, and higher proportions of perineural invasion, microsatellite instability, obstruction, and perforation than T1-2N1 cancers. Peritoneal seeding and liver metastasis were the predominant recurrence pattern in the T4N0 and T1-2N1 groups, respectively (p = 0.042). The T4N0 group showed inferior survival to the T1-2N1 group in postoperative adjuvant chemotherapy (5-OS: 87.1 vs. 93.2 %, p = 0.045; 5-DFS: 76.1 vs. 89.0 %, p = 0.001). CONCLUSIONS: T4N0 colon cancer had significantly worse oncologic outcomes than T1-2N1 cancer regardless of adjuvant chemotherapy. The survival paradox may result from the biologic aggressiveness of T4N0 colon carcinomas.

KRAS mutation is associated with worse prognosis in stage III or high-risk stage II colon cancer patients treated with adjuvant FOLFOX.

BACKGROUND: Although KRAS mutation has a predictive role in stage IV colorectal cancer (CRC) patients treated with anti-EGFR therapy, there have been controversies in the prognostic impact of KRAS mutation in stage II or III disease. The purpose of this study was to assess the prognostic impact of KRAS and BRAF mutation in patients treated with adjuvant 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX). METHODS: KRAS exon 2 and BRAF codon 600 were analyzed in patients with stage II and III CRC who underwent curative resection followed by adjuvant FOLFOX. Clinicopathologic features and disease-free survival (DFS) were compared. RESULTS: Among a total of 437 patients, mutational data of KRAS and BRAF were available in 388 and 433 patients, respectively. KRAS mutation (codon 12 and 13) and BRAF V600E mutation was found in 26.5 and 3.7 % of patients. DFS was significantly worse in the KRAS mutant patients compared to KRAS wild type patients (3-year DFS 79 and 92 %, p = 0.006). Multivariate analysis revealed KRAS mutation as an independent negative prognostic factor for DFS (adjusted hazard ratio 2.30, 95 % confidence interval 1.23-4.32). Among the various subtypes of KRAS mutation, G13D (3-year DFS 76 %, p = 0.008) was significantly associated with poor DFS, while G12D was not associated with prognosis (3-year DFS 86 %, p = 0.61). There was no association between BRAF mutation and DFS. CONCLUSIONS: KRAS mutation has an adverse prognostic impact on stage II or III CRC treated with adjuvant FOLFOX.

Histopathologic factors affecting tumor recurrence after hepatic resection in colorectal liver metastases.

PURPOSE: Hepatic resection is a standard method of treatment for colorectal liver metastases (CRLM). However, the pathologic factors of metastatic lesions that affect tumor recurrence are less well defined in CRLM. The aim of this study was to evaluate the risk factors for recurrence of CRLM, focusing on histopathologic factors of metastatic lesions of the liver. METHODS: From January 2003 to December 2008, 117 patients underwent curative hepatic resection for CRLM were reviewed. Tumor size and number, differentiation, tumor budding, angio-invasion, dedifferentiation and tumor infiltrating inflammation of metastatic lesions were investigated. RESULTS: The mean number of hepatic tumors was 2 (range, 1-8). The mean size of the largest tumor was 2.9 cm (range, 0.3-18.5 cm) in diameter. The moderate differentiation of the hepatic tumor was the most common in 86.3% of the patients. Tumor budding, angio-invasion, and dedifferentiation were observed in 81%, 34%, and 12.8% of patients. Inflammation infiltrating tumor was detected in 6.8% of patients. Recurrence after hepatic resection appeared in 69 out of 117 cases (58.9%). Recurrence-free survival at 1, 2 and 5 years were 62.4%, 43.6%, and 34.3%. The multivariate analysis showed the number of metastases ≥3 (P = 0.007), the tumor infiltrating inflammation (P = 0.047), and presence of dedifferentiation (P = 0.020) to be independent risk factors for tumor recurrence. CONCLUSION: Histopathological factors, i.e., dedifferentiation and tumor infiltrating inflammation of the metastatic lesion, could be one of the risk factors of aggressive behavior as well as the number of metastases even after curative resection for CRLM.

RNA editing in RHOQ promotes invasion potential in colorectal cancer.

RNA editing can increase RNA sequence variation without altering the DNA sequence. By comparing whole-genome and transcriptome sequence data of a rectal cancer, we found novel tumor-associated increase of RNA editing in ras homologue family member Q (RHOQ) transcripts. The adenosine-to-inosine (A-to-I) editing results in substitution of asparagine with serine at residue 136. We observed a higher level of the RHOQ RNA editing in tumor compared with normal tissue in colorectal cancer (CRC). The degree of RNA editing was associated with RhoQ protein activity in CRC cancer cell lines. RhoQ N136S amino acid substitution increased RhoQ activity, actin cytoskeletal reorganization, and invasion potential. KRAS mutation further increased the invasion potential of RhoQ N136S in vitro. Among CRC patients, recurrence was more frequently observed in patients with tumors having edited RHOQ transcripts and mutations in the KRAS gene. In summary, we show that RNA editing is another mechanism of sequence alteration that contributes to CRC progression.

The influence of the treatment response on the impact of resection margin status after preoperative chemoradiotherapy in locally advanced rectal cancer.

BACKGROUND: Circumferential resection margin (CRM) and distal resection margin (DRM) have different impact on clinical outcomes after preoperative chemoradiotherapy (CRT) followed by surgery. Effect and adequate length of resection margin as well as impact of treatment response after preoperative CRT was evaluated. METHODS: Total of 403 patients with rectal cancer underwent preoperative CRT followed by total mesorectal excision between January 2004 and December 2010. After applying the criterion of margin less than 0.5 cm for CRM or less than 1 cm for DRM, 151 cases with locally advanced rectal cancer were included as a study cohort. All patients underwent conventionally fractionated radiation with radiation dose over 50 Gy and concurrent chemotherapy with 5-fluorouracil or capecitabine. Postoperative chemotherapy was administered to 142 patients (94.0%). Median follow-up duration was 43.1 months. RESULTS: The 5-year overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS) rates, and locoregional control rates (LRC) were 84.5%, 72.8%, 74.2%, and 86.3%, respectively. CRM of 1.5 mm and DRM of 7 mm were cutting points showing maximal difference in a maximally selected rank method. In univariate analysis, CRM of 1.5 mm was significantly related with worse clinical outcomes, whereas DRM of 7 mm was not. In multivariate analysis, CRM of 1.5 mm, and ypN were prognosticators for all studied endpoints. However, CRM was not a significant prognostic factor for good responders, defined as patients with near total regression or T down-staging, which was found in 16.5% and 40.5% among studied patients, respectively. In contrast, poor responders demonstrated a significant difference according to the CRM status for all studied end-points. CONCLUSIONS: Close CRM, defined as 1.5 mm, was a significant prognosticator, but the impact was only prominent for poor responders in subgroup analysis. Postoperative treatment strategy may be individualized based on this finding. However, findings from this study need to be validated with larger cohort.

Establishment and characterization of seven human breast cancer cell lines including two triple-negative cell lines.

Permanently growing cell lines can be invaluable because of their usefulness in a variety of experimental situations. We report the characteristics of seven cell lines designated, SNU-306, SNU-334, SNU-1528, SNU-1553, SNU-1581, SNU-1958 and SNU-2372, which were established from three primary carcinomas, two pleural effusion, one pericardial effusion and one ascitic fluid samples obtained from seven Korean breast carcinoma patients. The histopathology of the primary tumors and their in vitro growth characteristics are described. DNA fingerprinting analysis and genetic alterations in the p53 and EGFR genes were conducted. The expression levels of the ER-α, PR, C-erbB2, E-cadherin, COX-2, MDR and MXR genes were investigated and sensitivity to anticancer drugs was screened. Growth was as adherent cells (four cell lines), floating aggregates (one cell line) and both (two cell lines). All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis using 18 microsatellite markers. Estrogen receptor (ER) mRNA was highly expressed in five cell lines and low or undetectable in SNU-1958 and SNU-2372. Progesterone receptor (PR) mRNA was expressed only in the SNU-306. SNU-1958 and SNU-2372 were hormone receptor-negative and C-erbB2-negative (triple-negative). SNU-1528 had an in-frame deletion of 42 base pairs of p53 gene and showed over 20-fold resistance for taxol compared to the other cell lines. There were no mutation in the EGFR gene; COX-2 was expressed in four cell lines and MXR was expressed in two cell lines. These well-characterized seven breast cancer cell lines, which include two triple-negative cell lines, will be useful for the study of breast cancer biology.

Targeted sequencing of cancer-related genes in colorectal cancer using next-generation sequencing.

Recent advance in sequencing technology has enabled comprehensive profiling of genetic alterations in cancer. We have established a targeted sequencing platform using next-generation sequencing (NGS) technology for clinical use, which can provide mutation and copy number variation data. NGS was performed with paired-end library enriched with exons of 183 cancer-related genes. Normal and tumor tissue pairs of 60 colorectal adenocarcinomas were used to test feasibility. Somatic mutation and copy number alteration were analyzed. A total of 526 somatic non-synonymous sequence variations were found in 113 genes. Among these, 278 single nucleotide variations were 232 different somatic point mutations. 216 SNV were 79 known single nucleotide polymorphisms in the dbSNP. 32 indels were 28 different indel mutations. Median number of mutated gene per tumor was 4 (range 0-23). Copy number gain (>X2 fold) was found in 65 genes in 40 patients, whereas copy number loss (

Pharmacogenetic analysis of adjuvant FOLFOX for Korean patients with colon cancer.

PURPOSE: Ethnic diversity of genetic polymorphism can result in individual differences in the efficacy and toxicity of cancer chemotherapy. METHODS: We analyzed 20 germline polymorphisms in 10 genes (TS, MTHFR, ERCC1, XPD, XRCC1, ABCC2, AGXT, GSTP1, GSTT1 and GSTM1) from prospectively enrolled 292 Korean patients treated with adjuvant oxaliplatin plus leucovorin plus 5-fluorouracil (FOLFOX) for colon cancer. RESULTS: In contrast to previous studies in Caucasians, neutropenia (grade 3-4, 60.5 %) was frequently observed, whereas only 16.4 % experienced grade 2 or more sensory neuropathy. Neutropenia was more frequent in MTHFR 677TT [adjusted odds ratio (OR) 2.32, 95 % confidence interval (CI) 1.19-4.55] and ERCC1 19007TT (adjusted OR 4.58, 95 % CI 1.20-17.40) genotypes. Patients harboring XRCC1 23885GG experienced less grade 2-4 neuropathy [adjusted OR 0.52, 95 % CI 0.27-0.99]. MTHFR 677TT (p = 0.002) and XRCC1 23885GG (p = 0.146) genotypes were also more prevalent in Koreans compared to Caucasians. TS 'low' genotype (adjusted HR 1.83, 95 % CI 1.003-3.34) was significantly related to shorter disease-free survival. Overall survival was not significantly different according to the polymorphisms. CONCLUSIONS: Polymorphisms in MTHFR, XRCC1 and TS are related to toxicities and disease-free survival in patients with colon cancer. The ethnic differences in frequencies of genotypes may explain the ethnic difference in toxicity profile following adjuvant FOLFOX chemotherapy.

Methylation and microsatellite status and recurrence following adjuvant FOLFOX in colorectal cancer.

The prognostic impact of CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) on the treatment outcome of colon cancer patients receiving adjuvant 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX) is unclear. We investigated CIMP and MSI status in colorectal cancer patients treated with adjuvant FOLFOX. Stages II and III sporadic colorectal cancer patients who underwent curative resection followed by adjuvant FOLFOX were included. Eight CpG island loci (CACNA1G, CRABP1, IGF2, MLH1, NEUROG1, CDKN2A (p16), RUNX3 and SOCS1) and five microsatellite markers were examined. Disease-free survival (DFS) was analyzed according to CIMP and MSI status. A total of 322 patients were included: male/female 192/130, median age 61 years (range 30-78), proximal/distal location 118/204 and Stages II/III 43/279. CIMP status was high in 25 patients (7.8%) and 21 patients (6.5%) had MSI-high tumor. CIMP/MSI status was not significantly associated with DFS: 3-year DFS 100% in CIMP(-)/MSI(+), 84% in CIMP(-)/MSI(-), 82% in CIMP(+)/MSI(-) and 75% in CIMP(+)/MSI(+) (p = 0.33). Results of exploratory analysis showed that concurrent methylation at NEUROG1 and CDKN2A (p16) was associated with shorter DFS: 3-year DFS 69% in NEUROG1(+)/CDKN2A (p16)(+) versus 87% in NEUROG1(-)/CDKN2A (p16)(-) (p = 0.006). In conclusion, concurrent methylation of NEUROG1 and CDKN2A (p16) is associated with recurrence following adjuvant FOLFOX in Stages II/III colorectal cancer.

Depth of mesorectal extension has prognostic significance in patients with T3 rectal cancer.

BACKGROUND: More than half of all rectal cancers are T3 lesions, but they are classified as a single-stage category. OBJECTIVE: The aim of this study was to validate prognostic significance of mesorectal extension depth in T3 rectal cancer. DESIGN: This study is a retrospective analysis of oncologic outcomes of patients with T3 rectal cancer grouped by mesorectal extension depth (T3a, <1 mm; T3b, 1-5 mm; T3c, 5-15 mm; T3d, >15 mm). SETTINGS: This study was conducted at a tertiary referral cancer hospital. PATIENTS: From 2003 to 2009, 291 patients who underwent a curative surgery were included. MAIN OUTCOME MEASURES: Oncologic outcomes in terms of disease-free survival were analyzed. RESULTS: The 5-year disease-free survival rate according to T3 subclassification was 86.5% for T3a, 74.2% for T3b, 58.3% for T3c, and 29.0% for T3d. It was significantly higher in T3a,b tumors than that in T3c,d tumors (77.6% vs 55.2%, p < 0.001). On univariate and multivariate analysis, prognostic factors affecting recurrence were preoperative CEA level ≥ 5 ng/mL (HR 2.617, 95% CI 1.620-4.226), lymph node metastasis (HR 3.347, 95% CI 1.834-6.566), and mesorectal extension depth >5 mm (HR 1.661, 95% CI 1.013-2.725). In subgroup analysis, independent prognostic factors were preoperative CEA level and mesorectal extension depth >5 mm for 200 patients with ypT3 rectal cancer and preoperative CEA level and lymph node metastasis for 91 patients with pT3 rectal cancer. LIMITATIONS: This study lacks quality of surgery plane evaluation because of its retrospective nature. Moreover, pathologic examination was not done with a whole-mount section. CONCLUSIONS: Depth of mesorectal extension >5 mm is a significant prognostic factor in patients with T3 rectal cancer. Depth of mesorectal extension especially may be more important than the nodal status in predicting the oncologic outcome for patients who had received preoperative chemoradiotherapy.

Notch1 counteracts WNT/ß-catenin signaling through chromatin modification in colorectal cancer.

Crosstalk between the Notch and wingless-type MMTV integration site (WNT) signaling pathways has been investigated for many developmental processes. However, this negative correlation between Notch and WNT/ß-catenin signaling activity has been studied primarily in normal developmental and physiological processes in which negative feedback loops for both signaling pathways are intact. We found that Notch1 signaling retained the capability of suppressing the expression of WNT target genes in colorectal cancers even when ß-catenin destruction by the adenomatous polyposis coli (APC) complex was disabled. Activation of Notch1 converted high-grade adenoma into low-grade adenoma in an Apcmin mouse colon cancer model and suppressed the expression of WNT target genes in human colorectal cancer cells through epigenetic modification recruiting histone methyltransferase SET domain bifurcated 1 (SETDB1). Extensive microarray analysis of human colorectal cancers also showed a negative correlation between the Notch1 target gene, Notch-regulated ankyrin repeat protein 1 (NRARP), and WNT target genes. Notch is known to be a strong promoter of tumor initiation, but here we uncovered an unexpected suppressive role of Notch1 on WNT/ß-catenin target genes involved in colorectal cancer.

Does t3 subdivision correlate with nodal or distant metastasis in colorectal cancer?

PURPOSE: We analyzed the clinical data of T3 colorectal cancer patients to assess whether T3 subdivision correlates with node (N) or metastasis (M) staging and stage-independent factors. METHODS: Five hundred fifty-five patients who underwent surgery for primary colorectal cancer from January 2003 to December 2009 were analyzed for T3 subdivision. T3 subdivision was determined by the depth of invasion beyond the outer border of the proper muscle (T3a, <1 mm; T3b, 1 to 5 mm; T3c, >5 to 15 mm; T3d, >15 mm). We investigated the correlation between T3 subdivision and N, M staging and stage-independent prognostic factors including angiolymphatic invasion (ALI), venous invasion (VI) and perineural invasion (PNI). RESULTS: The tumors of the 555 patients were subclassified as T3a in 86 patients (15.5%), T3b in 209 patients (37.7%), T3c in 210 patients (37.8%) and T3d in 50 patients (9.0%). The nodal metastasis rates were 39.5% for T3a, 56.5% for T3b, 75.7% for T3c and 74.0% for T3d. The distant metastasis rates were 7.0% for T3a 9.1% for T3b, 27.1% for T3c and 40.0% for T3d. Both N and M staging correlated with T3 subdivision (Spearman's rho = 0.288, 0.276, respectively; P < 0.001). Other stage-independent prognostic factors correlated well with T3 subdivision (Spearman's rho = 0.250, P < 0.001 for ALI; rho = 0.146, P < 0.001 for VI; rho = 0.271, P < 0.001 for PNI). CONCLUSION: Subdivision of T3 colorectal cancer correlates with nodal and metastasis staging. Moreover, it correlates with other prognostic factors for colorectal cancer.

Microsatellite instability testing in Korean patients with colorectal cancer.

Microsatellite instability (MSI) testing is useful for identifying patients with hereditary nonpolyposis colorectal cancer and detecting sporadic colorectal cancer that develops through replication error pathways. A pentaplex panel is recommended by the National Cancer Institute for MSI testing, but simplified mononucleotide panels and immunohistochemistry of mismatch repair proteins are widely employed for convenience. This study was to evaluate the MSI status of colorectal cancer in Korean patients. This study included 1,435 patients with colorectal adenocarcinoma subjected to surgical resection. The pentaplex Bethesda panel was used for MSI testing. Seventy nine (5.5 %) carcinomas were classified as MSI-high (MSI-H) and 95 (6.6 %) as MSI-low (MSI-L). BAT-26 and BAT-25 were unstable in 73 and 75 of 79 MSI-H carcinomas, respectively. With the panel comprising these 2 mononucleotide markers, 72 carcinomas were diagnosed as MSI-H, compared to the Bethesda panel data (72/79, 91.1 %). In contrast, BAT-26 or BAT-25 were unstable in only 7 (7.4 %) of the 95 MSI-L tumors. In the panel with 2 dinucleotide markers, D17250 linked to p53 and D2S123 to hMSH2, detection rates were 89.9 % (71/79) for MSI-H and 80.0 % (76/95) for MSI-L carcinomas, compared to the Bethesda panel. Moreover, we compared the frequency of MSI tumor in our patients with those reported previously from Western countries. In conclusion, the frequency of MSI-H appears lower in colorectal cancer patients in Korea. A simplified panel for MSI testing with BAT-26 and BAT-25 seems not effective for the accurate evaluation of MSI status, particularly in MSI-L colorectal carcinomas, in our patients.

Establishment and characterization of six human gastric carcinoma cell lines, including one naturally infected with Epstein-Barr virus.

We report the characterization of six new gastric carcinoma cell lines (designated NCC-19, NCC-20, NCC-24, NCC-59, SNU-1750 and SNU-1967) established from primary tumor samples of Korean patients. Four cell lines grew as adherent monolayers, one as both adherent and floating cell clumps and one as floating cell aggregates. The cell phenotypes, including the histopathology of the primary tumors and in vitro growth characteristics, were determined. We also performed molecular characterization, including DNA fingerprinting analysis and abnormalities of K-ras, p53, ß-catenin, and TGF-ßRII genes by PCR-SSCP and sequencing analyses. Population doubling times varied from 47-135 h. All cell lines showed relatively high viability, absence of mycoplasma or bacteria contamination and genetic heterogeneity by DNA fingerprinting analysis. Three lines had p53 mutations; one line had mutations in codon 13 (Gly13Asp) in K-ras and no line had a ß-catenin mutation. NCC-59 cell line had a -1-bp mutation in 10-bp poly deoxy adenine repeat tract of the TGF-ßRII gene. Moreover, NCC-24 gastric cancer cell line was found to be infected with Epstein-Barr virus (EBV). EBV infection was also shown in the original carcinoma tissue of the NCC-24 cell line. These well-characterized six gastric cancer cell lines should serve as useful tools for investigating the biological characteristics of gastric cancer and, in particular, NCC-24 may serve as a valuable model system to clarify the precise role of EBV in gastric carcinogenesis.

Comparison of surgical-site infection between open and laparoscopic appendectomy.

PURPOSE: An inflamed appendix can be removed either openly (open appendectomy [OA]) or laparoscopically (laparoscopic appendectomy [LA]). Surgical-site infection (SSI) is a representative healthcare-associated infection and can impose serious economic burdens on patients as well as affect morbidity and mortality rates. The aim of this study was to compare LA with OA in terms of SSI. METHODS: The medical records of 749 patients (420 males; mean age, 33 years) who underwent appendectomy (OA, 431; LA, 318) between September 1, 2008 and April 29, 2010 were retrospectively reviewed for demographic and pathologic characteristics, recovery of bowel movement, length of hospital stay, and postoperative complications. RESULTS: The frequency of purulent/gangrenous or perforated appendicitis was not significantly different between LA and OA groups (83% [263/318 cases] vs. 83% [359/431 cases], P = 0.183). The time to first flatus after surgery was not significantly different between the two groups (1.38 ± 1.07 days for LA, 1.33 ± 0.90 days for OA, P = 0.444), but the length of hospital stay was significantly shorter in LA group than in OA group (3.37 ± 0.12 days vs. 3.83 ± 0.12 days, P = 0.006). The frequency of overall SSI was not significantly different between the two groups (2.8% for LA, 4.6% for OA, P = 0.204), but that of superficial incisional SSI was significantly lower in LA group (0.6% vs. 3.9%, P = 0.016). CONCLUSION: The results of this study suggest that LA may lead to a shorter length of hospital stay and may have a lower risk of superficial incisional SSI than OA.

The impact of heavy smoking on anastomotic leakage and stricture after low anterior resection in rectal cancer patients.

BACKGROUND: Anastomotic complications after low anterior resection are associated with perianastomotic ischemia. Smoking is one of the main causes of microvascular disease that is correlated with tissue ischemia. The purpose of the present study was to assess the impact of smoking on anastomotic complications after low anterior resection in rectal cancer patients. METHODS: Between January 2005 and December 2008, 412 patients underwent low anterior resection for rectal cancers by a single surgeon at Seoul National University Hospital. Excluded from this series were 197 patients with postoperative radiation therapy, cancers that were located above 10 cm from the anal verge, or lack of medical records, and the remaining 215 patients were included for analysis. Significant variables in the univariate analysis were subsequently subject to multivariate analysis for identification of risk factors for complications. RESULTS: The rate of anastomotic complications was 10.7% (23 of 215 patients). Univariate analysis showed that male gender, body mass index higher than 25 kg/m(2), smoking history, smoking amount, type of operation, and presence of a protective stoma were associated with anastomotic complications. In multivariate analysis, a history of heavy smoking was a significant risk factor for anastomotic complications. CONCLUSIONS: A history of heavy smoking (more than 40 pack-years) is an independently significant risk factor for anastomotic complications after low anterior resection in rectal cancer patients.

Methylation-specific PCR.

DNA methylation patterns in CpG-rich regions of promoter, CpG islands, are concerned in regulation of gene expression in mammalian cells. Excessive methylation of CpG dinucleotides in promoter represses the gene expression. In cancer, especially, gene silencing is occurred through aberrant methylation in promoter of tumor suppressor genes. Methylation-specific PCR (MSP) is a method for analysis of DNA methylation patterns in CpG islands. For performing MSP, DNA is modified by and PCR performed with two primer pairs, which are detectable methylated and unmethylated DNA, respectively. MSP is a rapid measure for assession of the methylation status in CpG island.