<Emphasis Type="Italic"> BAX</Emphasis> and <Emphasis Type="Italic">caspase-5</Emphasis> frameshift mutations and spontaneous apoptosis in colorectal cancer with microsatellite instability

Background and aims Hereditary nonpolyposis colorectal cancer (HNPCC) and a subset of sporadic colorectal cancers are characterized by microsatellite instability (MSI) and inactivating frameshift mutations of target genes. Inactivation of BAX, caspase-5 (cas-5), and other genes coding for pro-apoptotic proteins might contribute to tumor progression by enhancing escape from apoptosis. The aim of this study was to further characterize the role of BAX and cas-5 inactivation for spontaneous apoptosis.Methods Twenty-five colorectal cancers with MSI were analyzed for frameshift mutations in the BAX (G)8 and cas-5 (A)10 tract by fluorescence PCR, cloning, and sequencing. The rate of spontaneous apoptosis was examined by in situ DNA nick end-labeling. The results were compared with 25 stage-matched microsatellite stable (MSS) colorectal cancers.Results In colorectal cancer with MSI frameshift mutations in BAX and cas-5 were present in 16 of 25 (64%) and in 12 of 25 (48%) tumors, respectively, whereas neither mutant BAX nor cas-5 alleles were detected in all stage-matched sporadic MSS colorectal cancer. Tumors with MSI showed a higher apoptotic rate than MSS tumors (2.5±1.0 vs. 2.1±0.7; p <0.05), whereas the presence of BAX or cas-5 frameshift mutations had only minor influence on this finding (2.4±1.1% and 2.5±0.9%, respectively).Conclusion Mismatch-repair deficiency itself is associated with increased spontaneous apoptosis, not further accelerated by either inactivating BAX or cas-5 frameshift mutations.This work was supported by grants from the Johann Wolfgang Goethe University Frankfurt a.M. (F15/01) and the Paul and Ursula Klein Foundation     

Comparison of Laparoscopic <Emphasis Type="Italic">vs.</Emphasis> Open Access Surgery in Patients with Rectal Cancer: A Prospective Analysis

Purpose Laparoscopic surgery of colon cancer has been accepted to be oncologically adequate compared with open resection. However, the situation in rectal cancer remains unclear, because anatomy and complex surgical procedures might specifically influence the long-term outcome. This study was designed to analyze perioperative and long-term outcome of patients with rectal cancer after laparoscopic vs. open access surgery. Methods A total of 389 patients (1998–2005) were prospectively analyzed; 114 patients had laparoscopic beginning, and 25 patients had conversion and were separately analyzed. Eighty-nine patients remained in the laparoscopic group and 275 had open access surgery. Results Both groups were comparable regarding age, gender, tumor localization, stage, and complications. Differences were found in harvested lymph nodes (laparoscopic 13.5/open access 16.9; P = 0.001) and hospitalization (15.1/18.7 days; P = 0.037). Local recurrence rate and metachronous metastasis were comparable. In patients with deep anterior resection with total mesenteric excision, favorable long-term survival in the laparoscopic group was found (P = 0.035, log-rank). Conclusions Minimally invasive surgery is equivalent in the treatment of rectal cancer and shows advantages of shorter hospitalization and faster recovery. Especially in patients with low rectal cancer, minimally invasive surgery with exact preparation of the total mesenteric excision seems to be favorable compared with open access surgery.     

<Emphasis Type="Italic">NAT2</Emphasis> Fast Acetylator Genotype is Associated with an Increased Risk of Colorectal Cancer in Taiwan

In Taiwan, colorectal cancer has one of the highest rates of increased incidence in the past two decades. Heterocyclic amines from dietary cooked meats are metabolically activated by NAT2 (N-acetyltransferase 2), which are associated with colorectal cancer incidence. Thus, the NAT2 fast acetylator genotype may be associated with colorectal cancer risk. However, the association between the NAT2 genotype and colorectal cancer risk is not clearly understood. We conducted a study with 244 primary colorectal cancer cases and 299 cancer-free healthy control subjects to verify the association of NAT2 polymorphisms with the risk of Taiwanese colorectal cancer. Our data showed that subjects with the NAT2 W/W homozygous genotype had a 1.63-fold increased risk of colorectal cancer compared with those with the Mx/Mx slow acetylator genotype (95 percent confidence interval, 1.03–2.58); however, no risk was found in the W/Mx heterozygous and Mx/W+W/W fast acetylator genotypes. Being stratified by gender factors, the colorectal cancer risk in females with homozygous W/W or Mx/W+W/W fast acetylators increased 2.47-fold and 2.13-fold compared with those with the Mx/Mx slow acetylator genotype (95 percent confidence interval, 1.27–4.82 for W/W genotype; 95 percent confidence interval, 1.17–3.89 for Mx/W+W/W genotype); however, the risk of the NAT2 genotype and colorectal cancer was not observed in males. Collectively, patients with the NAT2 fast acetylator genotype were more prone to colorectal cancer and reflected the possibility that exposure to heterocyclic amines may contribute to colorectal cancer development in Taiwan, especially in Taiwanese females. Supported by grants from the Department of Health (DOH 94-TD-G-111-017) and the National Science Council (NSC95-2314-B-040-041, NSC95-2314-b040-002), The Executive Yuan, Republic of China. Presented at the Conference of Biomedical Sciences, Taipei, Taiwan, March 17 to 18, 2007. Chi-Chou Huang and Wen-Pin Chien contributed equally to this work.     

Long-Term Survival in Patients with Locally Advanced Colon Cancer After <Emphasis Type="Italic">En Bloc</Emphasis> Pancreaticoduodenectomy and Colectomy

Purpose  Surgical indications for colon cancer directly invading the pancreas head are controversial. Methods  Between 1957 and 2007, a total of 12 patients (8 men) underwent pancreaticoduodenectomy combined with right hemicolectomy for colon cancer involving the pancreas head. Results  Mean age was 58 (range, 34–77) years. Fistula formation was observed in five patients (41 percent) preoperatively. Tumor involvement was duodenum only (n = 4), duodenum/pancreas (n = 3), stomach/pancreas (n = 1), duodenum/stomach (n = 2), duodenum/liver (n = 1), and pancreas only (n = 1). Only one postoperative death was encountered. Histologic examination showed malignant invasion to the pancreas head in nine cases (75 percent). Overall one-year, three-year and, five-year survival rates after surgery were 75, 66, and 55 percent, respectively. Five patients (41 percent) survived for more than ten 10 years. Conclusions  Pancreaticoduodenectomy for advanced colon cancer invading the pancreas or duodenum provides favorable long-term survival. Supported by a Grant-in-Aid for Basic Research to Dr. Akio Saiura from the Ministry of Education, Culture, Sports, Science and Technology. Reprints are not available.     

Patterns of Diagnosis for Colorectal Cancer: Screening Detected <Emphasis Type="Italic">vs.</Emphasis> Symptomatic Presentation

Purpose Colorectal cancer is a leading cause of cancer death in North America; studies have shown that screening improves survival. Conducted in British Columbia, Canada, this study was performed to identify the proportion of screening-eligible patients with sporadic colorectal cancer who are detected by screening tests vs. symptomatic presentation and to compare baseline patient and tumor characteristics of these two groups. Methods This retrospective cohort study identified 571 consecutive patients referred to the British Columbia Cancer Agency at aged 50 years and older presenting with a first diagnosis of invasive colorectal cancer between November 2002 and April 2003. Questionnaires for self-completion were mailed to all patients to capture: previous screening history, screening vs. symptomatic presentation, and demographic information. Results Of 212 eligible respondents (37 percent response), 14 patients (6.6 percent) with a new CRC were detected by screening vs. 198 patients (93.4 percent) presenting with symptoms. Respondents were 59 percent male, average age at diagnosis was 69 years, 91 percent white, 37 percent rectal, and 18 percent M1 at diagnosis. No significant differences in the age, gender, ethnicity, socioeconomic status, tumor stage, and site were detected between the screened vs. symptomatic cohorts. Only 33 of 212 patients (15.6 percent) reported ever having a screening test. Nineteen of 198 cancers (9.6 percent) were diagnosed by symptomatic presentation despite a compliant screening history. Conclusions Less than 7 percent of patients with a new diagnosis of CRC were detected via a screening test. Furthermore, only 15 percent of screening-eligible respondents had ever been screened. Significant effort is required to increase knowledge and compliance for CRC screening. Poster presentation at the meeting of the American Society of Clinical Oncologists, Atlanta, Georgia, June 2 to 6, 2006.     

Day-Case Stapled (Circular) <Emphasis Type="Italic">vs</Emphasis>. Diathermy Hemorrhoidectomy

PURPOSE: Stapled hemorrhoidectomy may be associated with less pain and faster recovery than conventional hemorrhoidectomy for prolapsing hemorrhoids. Therefore, the outcome of stapled hemorrhoidectomy was compared with that of diathermy hemorrhoidectomy in a randomized, controlled trial. METHODS: Sixty patients with third-degree hemorrhoids were randomly assigned to stapled hemorrhoidectomy (n = 30) or to diathermy hemorrhoidectomy in a day-case setting. Visual analog scale was used for postoperative pain scoring. Surgical and functional outcome was assessed at six weeks and one year after surgery. RESULTS: Operation time was a median of 21 (range, 11–59) minutes in the stapled group vs. 22 (range, 14–40) minutes in the diathermy group. Day-case surgery was successful in 24 patients (80 percent) in the stapled group vs. 29 patients (97 percent) in the diathermy group. Average pain in the stapled group was significantly lower than in the diathermy group (median, 1.8 (0.1–4.8) vs. 4.3 (1.4–6.2), 95 percent confidence interval difference medians, 1.15–3.85, P = 0.0002, Mann-Whitney U test) as was the average pain expected by the patients (median –2.7 (–0.15–0.8) vs. 0.006 (–4.05–0.5) respectively, 95 percent confidence interval difference medians, 0.5–3.55, P = 0.0018, Mann-Whitney U test). Postoperative morbidity and time off work were not significantly different between the diathermy and stapled groups. Seven treatment failures in the stapled group and one in the diathermy group necessitated other treatments at a later date. Patient satisfaction scores in the stapled and diathermy group were similar. Symptoms attributed to difficult rectal evacuation decreased significantly after surgery. CONCLUSIONS: Stapled hemorrhoidectomy is a significantly less painful operation than diathermy hemorrhoidectomy, but does not seem to offer significant advantages in terms of hospital stay or symptom control in the long term. Hemorrhoidectomy may improve symptoms of difficult rectal evacuation.     

Primary <Emphasis Type="Italic">vs</Emphasis>. Delayed Resection for Obstructive Left-Sided Colorectal Cancer: Impact of Surgery on Patient Outcome

Purpose By comparing surgical outcomes between primary and delayed resection, we addressed whether and how surgical strategies impacted prognosis of patients with left-sided colorectal cancer underwent emergency curative resection. Methods Between January 1980 and December 2002, a total of 143 patients were identified who presented with obstructive left-sided colorectal cancer and received emergency curative resection in Taipei Veterans General Hospital. Patients were stratified according to the timing of tumor resection into two groups: primary resection and delayed resection. Demographic data of the patients, characteristics of the tumors, and short-term and long-term outcomes were analyzed and compared between the two groups. Results The demographic data and tumor characteristics did not differ between the two groups except for more rectal cancers in the delayed resection group (P = 0.021). Primary resection group had a higher anastomotic leakage rate (P = 0.017) and a trend toward a higher mortality rate, which did not reach statistical significance (P = 0.063). The median follow-up intervals were similar (60.4 vs. 58.3 months; P = 0.79). The median survival tended to be longer in delayed resection group (66 vs. 105 months; P = 0.088). Overall five-year and ten-year survival for primary resection were 43.7 and 31.9 percent, respectively, compared with 67.2 and 53.2 percent, respectively, for delayed resection. Conclusions Delayed resection seems to be a safer procedure and provided a better oncologic outcome compared with primary resection in obstructive left-sided colorectal cancer under emergency situations. Supported by the Taipei Veterans General Hospital Research Fund (VGH92-B262).     

A Case-Control Study of Laparoscopic Right Hemicolectomy <Emphasis Type="Italic">vs.</Emphasis> Open Right Hemicolectomy

PURPOSE The purpose of our study was to examine all laparoscopic right hemicolectomies performed for cancer in our unit and to compare them with a case-control series of open right hemicolectomies, with emphasis on long-term survival.METHODS In a retrospective case-control series of right hemicolectomies, those done laparoscopically were compared with an age-matched and stage-matched series of patients who underwent open surgery. Survival was analyzed with the Kaplan-Meier method.RESULTS Ninety-nine patients were included in the study, 33 laparoscopic and 66 open. Mean age 69.7 years. Dukes staging was the same between the two groups and mean follow-up period was 65.7 months. There were six laparoscopic conversions. The number of days patients were kept nil by mouth was significantly less in the laparoscopic cohort, with a mean of 2.4 days vs. a mean of 3.65 days (P = 0.005, Mann-Whitney U test). The number of days during which patients required parenteral opiates was significantly less in the laparoscopic cohort, with a mean number of days of 2.5, in contrast to 4.5 days in the open group (P = 0.008, Mann-Whitney U test). When overall survival was compared between the open and laparoscopic groups, no difference was found, with a mean overall survival of 40 months in the laparoscopic cohort and 39.4 months in the open cohort (P = 0.348, log-rank test).CONCLUSION Laparoscopic right hemicolectomy for cancer does not compromise long-term survival and affords the advantage of a shorter period of postoperative ileus and decreased analgesia requirements.     

Postoperative Urinary Retention After Primary Colorectal Cancer Resection <Emphasis Type="Italic">via</Emphasis> Laparotomy: A Prospective Study of 2,355 Consecutive Patients

Purpose The risk factors for postoperative urinary retention after colorectal carcinoma surgery can be clearly defined. This study was designed to determine risk factors for postoperative urinary retention after colorectal cancer surgery. Methods A total of 2,355 consecutive patients with colorectal cancer who underwent open resection for colorectal cancer during a four-year period were included. The association between dependent and independent variables (including 19 clinicopathologic and surgical factors) was analyzed by using the chi-squared test or Fisher’s exact test, as appropriate. The significant variables in the univariate analyses were included in multivariate analysis. Results The overall prevalence of postoperative urinary retention was 5.5 percent (colon cancer, 1.7 percent; rectal cancer, 9.1 percent, P < 0.0001). Multivariate analysis showed an independent association between postoperative urinary retention and age, lung disease, tumor location, operation duration, and additional pelvic procedure. Of the 121 patients with postoperative urinary retention, urine catheterization was required in 42 patients one month postoperatively. Discriminate analysis showed that gender, American Society of Anesthesiologists’ score, tumor location, presence of drainage, and pelvic infection were best able to discriminate between prolonged (>1 month) and transient urinary dysfunction. Conclusions Older patients, lung disease, rectal cancer, longer operation duration, and additional pelvic procedure were at greater risk. There is a time-dependent change in postoperative urinary dysfunction. Male gender, American Society of Anesthesiologists’ score of 2 or 3, rectal tumor, surgical drain, and pelvic infection can identify patients at risk for prolonged urinary dysfunction.     

<Emphasis Type="Italic">Anisakis</Emphasis> spp. burden in <Emphasis Type="Italic">Trachurus trachurus</Emphasis>

Anisakis is a parasite of marine mammals that uses a great number of fish species as intermediate or paratenic hosts. It is common in commercially important marine fishes and its presence is of great concern for both human health and economic reasons. Horse mackerels (Trachurus trachurus) originated from the Northern Aegean Sea were examined for the presence of Anisakis spp. larvae. The prevalence of Anisakis spp. was found 98.8 %. The number of parasites was significantly related to the host’s length but was not related to the fish gender. The month of sampling affected the size of the fishes and consequently the number of parasites. The length of larvae was not related to the host’s length. The present study resulted in the design of a prediction model for the number of existing parasites in the fish by measuring only its Fixed Length.     

Characteristics and Survival Patterns of Solid Organ Transplant Patients Developing <Emphasis Type="Italic">De Novo</Emphasis> Colon and Rectal Cancer

PURPOSE Immunosuppression used in transplantation is associated with an increased incidence of various cancers. Although the incidence of colorectal cancer in transplant patients seems to be equal to nontransplant population, the effects of immunosuppression on patients who develop colorectal cancer are not well defined. The purpose of this study was to define the characteristics and survival patterns of transplant patients developing de novo colorectal cancer.METHODS The Israel Penn International Transplant Tumor Registry was queried for patients with colorectal cancer. Analysis included patient demographics, age at transplantation and colorectal cancer diagnosis, tumor stage, and survival. Age and survival rates were compared to United States population-based colorectal cancer statistics using the National Cancer Institute Surveillance Epidemiology and End Results database.RESULTS A total of 150 transplant patients with de novo colorectal cancer were identified: 93 kidney, 29 heart, 27 liver, and 1 lung. Mean age at transplantation was 53 years. Age at transplantation and colorectal cancer diagnosis was not significant for gender, race, or stage of disease. Compared to National Cancer Institute Surveillance Epidemiology and End Results database, transplantat patients had a younger mean age at colorectal cancer diagnosis (58 vs. 70 years; P < 0.001), and a worse five-year survival (overall, 44 vs. 62 percent, P < 0.001; Dukes A&B, 74 vs. 90 percent, P < 0.001; Dukes C, 20 vs. 66 percent, P < 0.001; and Dukes D, 0 vs. 9 percent, P = 0.08). CONCLUSIONS Transplant patients develop colorectal cancer at a younger age and exhibit worse five-year survival rates than the general population. These data suggest that chronic immunosuppression results in a more aggressive tumor biology. Frequent posttransplantation colorectal cancer screening program may be warranted.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, New Orleans, Louisiana, June 21 to 26, 2003.     

<Emphasis Type="Italic">T-</Emphasis>Scores and <Emphasis Type="Italic">Z</Emphasis>-Scores

Bone mineral density (BMD) can be measured by a variety of techniques at several skeletal sites. Once measured, the manufacturers’ software uses the BMD to calculate a T-score and/or Z-score. Both T-scores and Z-scores are derived by comparison to a reference population on a standard deviation scale. The recommended reference group for the T-score is a young gender-matched population at peak bone mass, while the Z-score should be derived from an age-matched reference population. T-scores and Z-scores are widely quoted in scientific publications on osteoporosis and BMD studies, and are the values used for DXA diagnostic criteria and current clinical guidelines for the management of osteoporosis. Errors in BMD measurement, differences in reference populations, and variations in calculation methods used, can all affect the actual T-score and Z-score value. Attempts to standardize these values have made considerable progress, but inconsistencies remain within and across BMD technologies. This can be a source of confusion for clinicians interpreting BMD results. A clear understanding of T-scores and Z-scores is essential for correct interpretation of BMD studies in clinical practice.     

<Emphasis Type="Italic">Aspergillus</Emphasis> and <Emphasis Type="Italic">Penicillium</Emphasis> allergens: Focus on proteases

Penicillium and Aspergillus species are prevalent airborne fungi. It is imperative to identify and characterize their major allergens. Alkaline and/or vacuolar serine proteases are major allergens of several prevalent Penicillium and Aspergillus species. They are also major immunoglobulin (Ig) E-reacting components of the most prevalent airborne yeast, Rhodotorula mucilaginosa, and the most prevalent Cladosporium species, C. cladosporioides. IgE cross-reactivity has been detected among these major pan-fungal serine protease allergens. In addition, the alkaline serine protease of P. chrysogenum (Pen ch 13) induces histamine release from basophils of asthmatic patients, degrades the tight junction protein occludin, and stimulates release of proinflammatory mediators from human bronchial epithelial cells. In addition to induction of IgE and inflammatory airway responses, the alkaline serine protease allergen of A. fumigatus (Asp f 13) has synergistic effects on Asp f 2-induced immune response in mice. Studies of these serine protease major allergens elucidate the diverse allergic disease mechanisms and facilitate the development of better therapeutic strategies.     

Association of <Emphasis Type="Italic">Lewis</Emphasis> and <Emphasis Type="Italic">Secretor</Emphasis> gene polymorphisms and <Emphasis Type="Italic">Helicobacter pylori</Emphasis> seropositivity among Japanese-Brazilians

Background Secretor (Se) and Lewis (Le) genes are involved in the synthesis of Lewis b (Le^b) and type I antigens throughout the body, especially in the epithelial cells of gastric mucosa. Helicobacter pylori can attach to the gastric epithelial cells with the blood group antigen-binding adhesin, which binds to Le^b or H type I carbohydrate structures. In a previous study, a marked association between H. pylori seropositivity and polymorphism of the Se and Le genes was observed among Japanese outpatients of a gastroenterology clinic. The present work aims to investigate the associations between Se and Le gene polymorphisms and H. pylori infection among Japanese-Brazilians.Methods The subjects consisted of 942 healthy volunteer Japanese-Brazilians, who were tested for the presence of anti-H. pylori IgG antibodies and genotyped for Se and Le polymorphisms.Results The sex-age-adjusted odds ratios (aORs) for H. pylori seropositivity were 0.99 for the Sese genotype relative to the SeSe genotype (95% confidence interval [CI], 0.73–1.33), and 1.03 for sese relative to SeSe (95% CI, 0.71–1.48). On the other hand, the aOR for the subjects with the le allele (Lele or lele) relative to the LeLe genotype was 1.48 (95% CI, 1.07–1.79). When the Se and Le genotypes were analyzed in combination according to risk group, no statistically significant association was observed.Conclusions These results are inconsistent with previous work and may have been modulated by an external factor or some other unidentified factor. Japanese-Brazilians are genotypically the same as Japanese, but their lifestyle is adapted to that of Brazil. Further investigations are necessary to clarify this influence on susceptibility to H. pylori infection.     

Low presence of <Emphasis Type="Italic">p53</Emphasis> abnormalities in <Emphasis Type="Italic">H. pylori</Emphasis>-infected gastric mucosa and in gastric adenocarcinoma

Background: Alterations of the p53 gene and/or its abnormal protein accumulation have been observed in gastric cancer and preneoplastic lesions. Our aim was to assess possible associations between different H. pylori strains and p53 abnormalities in patients with dyspepsia and with gastric cancer. Methods: Seventy-five dyspeptic patients and 40 patients with gastric adenocarcinoma entered the study. H. pylori status was determined by the rapid urease test, histology, and polymerase chain reaction (PCR) analysis. Overexpression of the p53 protein was evaluated by immunohistochemistry. Detection of p53 mutations was done by direct DNA sequencing. Results: Fifty-four of the 75 (72.0%) dyspeptic patients and 27 of the 40 (67.5%) gastric cancer patients showed H. pylori infection. Cytotoxin-associated gene (cagA)-positive strains were found in 31 of the 54 (58%) dyspeptic patients and in 25 of the 27 (92.6%) neoplastic patients. As regards vacA, s2 strains showed the highest prevalence among dyspeptic patients (24 of 54 patients; 44.4%), whereas s1 strains were more expressed among cancer patients (23 of 27; 85.2%). Among the dyspeptic patients, 1 patient with duodenal ulcer showed p53 overexpression. Three mutations were identified by DNA sequencing: one in a patient with normal endoscopic findings and two in patients suffering from gastritis. Among the neoplastic patients, 16 subjects (40%) showed p53 overexpression (9 had diffuse-type and 7 intestinal-type cancer). Four mutations (10%) occurred in patients with intestinal-type gastric cancer. No association between p53 abnormalities (overexpression/mutation) and H. pylori infection was found in either group of patients. Conclusions: These results lead us to hypothesize that H. pylori infection does not affect the p53 pattern in gastric mucosa. Moreover, mutations of the p53 gene do not seem to be a predominant event in gastric carcinogenesis, at least in our populations. Received: December 14, 2001 / Accepted: May 17, 2002 RID="*" ID="*"  These authors contributed equally to the work RID="*" ID="*"  These authors contributed equally to the work Acknowledgments. The authors would like to thank Mrs B. D'Attoma and Mrs P. Fiorente for their valuable technical assistance, and Mrs M.V.C. Pragnell, B.A., for her help in revising the English. Reprint requests to: A. Di Leo     

Novel <Emphasis Type="Italic">hMSH</Emphasis>2, <Emphasis Type="Italic">hMSH</Emphasis>6 and <Emphasis Type="Italic">hMLH</Emphasis>1 gene mutations and microsatellite instability in sporadic colorectal cancer

Purpose To detect the hMSH2, hMSH6 and hMLH1 DNA mismatch repair gene mutations and microsatellite instability in somatic colorectal cancer.Patients and methods The mutations of hMSH2, hMSH6, and hMLH1 genes, including microsatellite instability of BAT-26, BAT-40, D2S123, D5S346 and D17S250 were analyzed in 31 patients with colorectal.Results The results revealed that eight cases (25.8%) harbored mutations in DNA mismatch repair genes. Of these, five novel mutations including I237V in exon 4 of hMSH2, ins T at codon 1196 in exon 7 of hMSH6, and ins G at codon 154 in exon 6, N158H in exon 6, and del A at codon 257 in exon 9 of hMLH1 were identified. Moreover, several intronic polymorphisms, including c–g transversion at IVS-1 nt211 + 9 of hMSH2, del T in poly T track at IVS-6 nt3559-5, ATCT duplicate in IVS-7 nt 3642 + 35 and t–g transversion at IVS-10 nt4080 + 185 of hMSH6 were demonstrated in these patients. In addition, seven cases (22.5%) exhibited microsatellite instability (MSI).Conclusion These results suggested that the inactivation of DNA mismatch repair genes and microsatellite instability may play a minor role in somatic colorectal cancer development.