Acidic pelvic drainage as a predictive factor for anastomotic leakage after surgery for patients with rectal cancer

Perianastomotic pH Monitoring for Early Detection of Anastomotic Leaks in Gastrointestinal Surgery: A Systematic Review of the Literature

IntroductionAnastomotic leak (AL) represents a significant complication following gastrointestinal (GI) surgery, contributing to increased morbidity and mortality. pH monitoring has emerged as a potential diagnostic tool for the early detection of AL, but its effectiveness and clinical utility remain to be fully elucidated. This review aims to summarise the evidence regarding perianastomotic pH monitoring for AL detection.MethodsA systematic search of relevant databases was conducted to identify pre-clinical and clinical studies investigating pH monitoring for AL detection following GI surgery. Studies were screened by two independent reviewers based on predefined inclusion and exclusion criteria. Data were extracted and presented as a narrative synthesis.ResultsA total of 10 studies were included in the review, comprising animal studies (n = 2), and human studies in upper GI (n = 3) and colorectal (n = 5) patients. Consistent findings of lower pH values in patients with AL across various postoperative time points were demonstrated. There was diversity in the pH detection method, in addition to variable frequency and timing of pH monitoring. Four studies reported a shorter time for AL detection with pH monitoring vs conventional methods, although no statistical comparisons were used. No standard pH cut-off value for AL detection was identified.ConclusionpH monitoring shows potential as a diagnostic tool for the early detection of AL following GI surgery. While the existing evidence supports its potential utility, further research is required to establish standardised protocols and assess its clinical impact.

C-Reactive Protein in Peritoneal Fluid for Predicting Anastomotic Leakage After Colorectal Cancer Surgery: A Systematic Review and Meta-Analysis

Background: Anastomotic leakage (AL) is a serious and potentially fatal complication that can occur after colorectal cancer (CRC) surgery, and it significantly affects patient recovery and increases morbidity. While serum C-reactive protein (CRP) is a recognized systemic inflammatory marker, the level of CRP in peritoneal fluid may serve as a more specific and localized biomarker for early AL detection. This meta-analysis explores the diagnostic potential of peritoneal fluid CRP, aiming to enhance postoperative care for CRC patients. Methods: A comprehensive literature search was conducted following the PRISMA guidelines. Eligible studies were included based on strict inclusion and exclusion criteria. Diagnostic accuracy was pooled using a random-effects model. The risk of bias was assessed using the QUADAS-2 tool. Results: The pooled sensitivity and specificity were 0.74 and 0.83, respectively, with an area under the curve (AUC) of 0.84, indicating good diagnostic accuracy. The overall diagnostic performance was consistent for sensitivity with no significant heterogeneity, but high heterogeneity was observed for specificity, suggesting variability between studies. Subgroup analysis revealed improved diagnostic performance between postoperative days 5-7 and higher CRP cut-off values (70-150 mg/L). The analysis confirmed the stability of the results through a sensitivity analysis and found no significant publication bias. Conclusions: Peritoneal fluid CRP is a reliable biomarker for detecting AL after CRC surgery, especially in the later postoperative period. However, heterogeneity in study methodologies and patient populations limits the generalizability of the findings. Future research should focus on standardizing protocols and exploring additional biomarkers to improve diagnostic accuracy.

Continuous pH monitoring using a sensor for the early detection of anastomotic leaks

Anastomotic leaks (AL) and staple line leaks are a serious post-operative complication that can develop following bariatric surgery. The delay in the onset of symptoms following a leak usually results in reactive diagnostics and treatment, leading to increased patient morbidity and mortality, and a clinical and economic burden on both the patient and the hospital. Despite support in literature for pH as a biomarker for early detection of AL, the current methods of pH detection require significant clinician involvement and resources. Presented here is a polyaniline (PANI)-based pH sensor that can be connected inline to surgical drains to continuously monitor peritoneal secretion in real time for homeostatic changes in pH. During this study, the baseline peritoneal fluid pH was measured in two pigs using the PANI sensor and verified using a benchtop pH probe. The PANI sensor was then utilized to continuously monitor the changes in the pH of peritoneal effluent, as a gastric leak was simulated. The inline sensors were able to detect the resulting local changes in drainage pH within 10 min of leak induction. The successful implementation of this sensor in clinical practice can both enable high efficiency continuous monitoring of patient status and drastically decrease the time required to detect AL, thus potentially decreasing the clinical and economic burden incurred by gastric leaks.

Predictive Factors for Anastomotic Leakage Following Colorectal Cancer Surgery: Where Are We and Where Are We Going?

Anastomotic leakage (AL) remains one of the most severe complications following colorectal cancer (CRC) surgery. Indeed, leaks that may occur after any type of intestinal anastomosis are commonly associated with a higher reoperation rate and an increased risk of postoperative morbidity and mortality. At first, our review aims to identify specific preoperative, intraoperative and perioperative factors that eventually lead to the development of anastomotic dehiscence based on the current literature. We will also investigate the role of several biomarkers in predicting the presence of ALs following colorectal surgery. Despite significant improvements in perioperative care, advances in surgical techniques, and a high index of suspicion of this complication, the incidence of AL remained stable during the last decades. Thus, gaining a better knowledge of the risk factors that influence the AL rates may help identify high-risk surgical patients requiring more intensive perioperative surveillance. Furthermore, prompt diagnosis of this severe complication may help improve patient survival. To date, several studies have identified predictive biomarkers of ALs, which are most commonly associated with the inflammatory response to colorectal surgery. Interestingly, early diagnosis and evaluation of the severity of this complication may offer a significant opportunity to guide clinical judgement and decision-making.

Bacteriological concentration of peritoneal drainage fluid could make an early diagnosis of anastomotic leakage following rectal resection

To investigate that the bacteriological concentration and pH value in peritoneal drainage fluid might serve as indicators of early diagnosis of anastomotic leakage following rectal resection. We prospectively analyzed consecutive patients who were treated for rectal diseases with anastomosis at the department of general surgery, the affiliated hospital of Nanjing University Medical School between August 2018 and December 2020. The bacteriological concentration and the pH value in peritoneal drainage fluid were tested on the first, fourth, seventh days postoperatively. A total of 300 consecutive patients underwent rectal resection were tested. 21 patients present with AL and the overall AL rate was 7%. The bacteriological concentration in peritoneal drainage fluid of AL group was significantly higher than that in non-AL group. The AUC value was 0.98 (95% confidence intervals 0.969-1.000) according to the ROC curve. The best cut-off value was 1143/uL. The sensitivity and specificity were 100% and 93.19% respectively. There was no difference of pH value between the AL and non-AL groups. According the results of present study, a high bacteriological concentration in peritoneal drainage fluid is a good marker for predicting and diagnosing AL following rectal resection. However, owing to the limitation of the sample, there was no validation attempt in the study. A large sample study is needed to validate the conclusion.

Predictive and Diagnostic Biomarkers of Anastomotic Leakage: A Precision Medicine Approach for Colorectal Cancer Patients

Development of an anastomotic leak (AL) following intestinal surgery for the treatment of colorectal cancers is a life-threatening complication. Failure of the anastomosis to heal correctly can lead to contamination of the abdomen with intestinal contents and the development of peritonitis. The additional care that these patients require is associated with longer hospitalisation stays and increased economic costs. Patients also have higher morbidity and mortality rates and poorer oncological prognosis. Unfortunately, current practices for AL diagnosis are non-specific, which may delay diagnosis and have a negative impact on patient outcome. To overcome these issues, research is continuing to identify AL diagnostic or predictive biomarkers. In this review, we highlight promising candidate biomarkers including ischaemic metabolites, inflammatory markers and bacteria. Although research has focused on the use of blood or peritoneal fluid samples, we describe the use of implantable medical devices that have been designed to measure biomarkers in peri-anastomotic tissue. Biomarkers that can be used in conjunction with clinical status, routine haematological and biochemical analysis and imaging have the potential to help to deliver a precision medicine package that could significantly enhance a patient's post-operative care and improve outcomes. Although no AL biomarker has yet been validated in large-scale clinical trials, there is confidence that personalised medicine, through biomarker analysis, could be realised for colorectal cancer intestinal resection and anastomosis patients in the years to come.

Drain fluid's pH predicts anastomotic leak in colorectal surgery: results of a prospective analysis of 173 patients

BACKGROUND

The early risk assessment of anastomotic leak (AL) after colorectal surgery is crucial. Several markers have been proposed, including peritoneal fluid's pH. Aim of the present study is to evaluate the role of drain fluid pH as predictor of AL.

METHODS

All patients undergoing colorectal surgery from January 2015 to December 2017 were considered eligible. Hartmann procedures, procedures including temporary ileostomy and emergency surgery were excluded. Drain fluid was submitted for pH and chemical-physical assessment on postoperative day 1 (POD1) and postoperative day 3 (POD3).

RESULTS

Out of 173 patients, those who developed AL showed a lower drain fluid's pH on POD1 and on POD3 compared to patients who did not (P<0.05). The plotted ROC curves identified 7.53 as pH cut-off on POD1 (AUC 0.80) and 7.21 on POD3 (AUC 0.86). With both the cut-offs, pH was an independent predictor of AL at multivariable analysis (P<0.001). pH<7.53 on POD1 and pH<7.21 on POD3 showed 93.75% sensitivity and 97% specificity respectively.

CONCLUSIONS

Drain fluid's pH on POD1 is useful to select patients who will not develop AL while on POD3 it might identify those requiring a more careful management.

Peritoneal fluid biomarkers in the detection of colorectal anastomotic leaks: a systematic review

PURPOSE

Anastomotic leak (AL) in colorectal surgery leads to significant morbidity, mortality and poorer oncological outcomes. Diagnosis of AL is frequently delayed as current methods of detection are not 100% sensitive or specific. 'Biomarkers', such as cytokines and markers of ischaemia, from the milieu of the anastomosis may aid early detection. This paper aims to review the evidence for their role in AL detection, allowing identification of targets for future research.

METHODS

A systematic review was performed using PubMed, MEDLINE and Cochrane Library databases. Papers concerning detection or prediction of AL with biomarkers were identified. References within the papers were used to identify further relevant articles.

RESULTS

Research has taken place in small cohorts with varying definitions of AL. Lactate has consistently been shown to be elevated in patients with intra-abdominal complications and ALs. pH on post-operative day 3 showed excellent specificity. Despite mixed results, a meta-analysis found that the cytokines tumour necrosis factor-α and interleukin-6 were elevated early in AL. Detection of bacteria in drain fluid by RT-PCR has good specificity but a high rate of false positives.

CONCLUSIONS

Peritoneal cytokines, lactate and pH have the potential to identify AL early. The consistency of the results for lactate and pH, alongside the fact that they are easy, quick and inexpensive to test, makes them the most attractive targets. Studies in larger cohorts with standardized definitions of AL are required to clarify their usefulness. Emerging biosensor technology may facilitate the development of small, low-cost and degradable intra-abdominal devices to measure peritoneal fluid biomarkers.

Systematic review of the role of biomarkers in diagnosing anastomotic leakage following colorectal surgery

BACKGROUND

Anastomotic leakage (AL) following colorectal surgery can be difficult to diagnose owing to varying clinical presentations. This systematic review aimed to assess biomarkers as potential diagnostic tests for preclinical detection of AL.

METHODS

A comprehensive literature review was conducted according to PRISMA guidelines. All published studies evaluating biomarkers, both systemic and peritoneal, in the context of AL following colorectal surgery were included. Studies were sought in three electronic databases (MEDLINE, PubMed and Embase) from January 1990 to June 2016.

RESULTS

Thirty-six studies evaluated 51 different biomarkers in the context of AL after colorectal surgery. Biomarkers included markers of ischaemia and inflammation, and microbiological markers, and were measured in both peritoneal drain fluid and the systemic circulation. The most commonly evaluated peritoneal drain fluid biomarkers were interleukin (IL) 6, IL-10 and tumour necrosis factor. Significantly raised drain levels in the early postoperative period were reported to be associated with the development of AL. C-reactive protein, procalcitonin and leucocytes were the most commonly evaluated systemic biomarkers with significant negative and positive predictive values. Associated area under the curve values ranged from 0·508 to 0·960.

CONCLUSION

Peritoneal drain fluid and systemic biomarkers are poor predictors of AL after colorectal surgery. Combinations of these biomarkers showed improvement in predictive accuracy.

Anti-proliferation effects and molecular mechanisms of action of tetramethypyrazine on human SGC-7901 gastric carcinoma cells

AIM

To investigate the effects of tetramethypyrazine (TMP) on proliferation and apoptosis of the human gastric carcinoma cell line 7901 and its possible mechanism of action.

METHODS

The viability of TMP-treated 7901 cells was measured with a 3-(4, 5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT) and cell apoptosis was analyzed by flow cytometry. The distribution of cells in different phases of cell cycle after exposure of TMPs was analyzed with flow cytometry. To investigate the molecular mechanisms of TMP-mediated apoptosis, the expression of NF-xBp65, cyclinD1 and p16 in SGC-7901 cells was analyzed by reverse transcription- polymerase chain reaction (RT-PCR) and western blotting.

RESULTS

TMP inhibited the proliferation of human gastric carcinoma cell line 7901 in dose and time dependent manners. Cell growth was suppressed by TMP at different concentrations (0.25, 0.5, 1.0, 2.0 mg/ml), the inhibition rate is 0.46%, 4.36%, 14.8%, 76.1% (48h) and 15.5%, 18.5%, 41.2%, 89.8% (72h) respectively. When the concentration of TMPs was 2.0mg/ml, G1-phase arrest in the SGC-7901 cells was significant based on the data for cell cycle distribution. RT-PCR demonstrated that NF-xBp65 and cyclin D1 mRNA expression was significantly down-regulated in 7901 cells treated with 2.0 mg/ml TMP for 72h (p<0.05), while the p16 mRNA level was up-regulated (p<0.05). The protein expression of NF-xBp65 and cyclin D1 decreased gradually with the increase in TMP concentration, compared with control cells (p<0.05), while expression of protein p16 was up-regulated (p<0.01).

CONCLUSION

TMP exhibits significant anti-proliferative and pro-apoptotic effects on the human gastric carcinoma cell line SGC-7901. NF-xBp65, cyclinD1 and p16 may also play important roles in the regulation mechanisms.

Carcinoma microsatellite instability status as a predictor of benefit from fluorouracil-based adjuvant chemotherapy for stage II rectal cancer

PURPOSE

Rectal cancers with high microsatellite-instable have clinical and pathological features that differentiate them from microsatellite-stable or low- frequency carcinomas, which was studied rarely in stage II rectal cancer, promoting the present investigation of the usefulness of microsatellite-instability status as a predictor of the benefit of adjuvant chemotherapy with fluorouracil in stage II rectal cancer.

PATIENTS AND METHODS

Data of 460 patients who underwent primary anterior resection with a double stapling technique for rectal carcinoma at a single institution from 2008 to 2012 were retrospectively collected. All patients experienced a total mesorectal excision (TME) operation. Survival analysis were analyzed using the Cox regression method.

RESULTS

Five-year rate of disease-free survival (DFS) was noted in 390 (84.8%) of 460 patients with stage II rectal cancer. Of 460 tissue specimens, 97 (21.1%) exhibited high-frequency microsatellite instability. Median age of the patients was 65 (50-71) and 185 (40.2%) were male. After univariate and multivariate analysis, microsatellite instability (p= 0.001), female sex (p< 0.05) and fluorouracil-based adjuvant chemotherapy (p< 0.001), the 3 factors were attributed to a favorable survival status independently. Among 201 patients who did not receive adjuvant chemotherapy, those cancers displaying high-frequency microsatellite instability had a better 5-year rate of DFS than tumors exhibiting microsatellite stability or low-frequency instability (HR, 13.61 [95% CI, 1.88 to 99.28]; p= 0.010), while in 259 patients who received adjuvant chemotherapy, there was no DFS difference between the two groups (p= 0.145). Furthermore, patients exhibiting microsatellite stability or low-frequency instability who received adjuvant chemotherapy had a better 5-year rate of DFS than patients did not (HR, 5.16 [95% CI, 2.90 to 9.18]; p< 0.001), while patients exhibiting high-frequency microsatellite instability were not connected with increased DFS (p= 0.696). It was implied that female patients had better survival than male.

CONCLUSION

Survival status after anterior resection of rectal carcinoma is related to the microsatellite instability status, adjuvant chemotherapy and gender. Fluorouracil-based adjuvant chemotherapy benefits patients of stage II rectal cancer with microsatellite-stable or low microsatellite-instable, but not those with high microsatellite- instable. Additionally, free of adjuvant chemotherapy, carcinomas with high microsatellite-instable have a better 5-year rate of DFS than those with microsatellite-stable or low microsatellite-instable, and female patients have a better survival as well.

A predictive model for evaluating responsiveness to pemetrexed treatment in patients with advanced colorectal cancer

PURPOSE

To highlight the potential factors that could predict the response rate of patients with metastatic colorectal cancer (mCRC) treated with pemetrexed combined chemotherapy after first- or second-line chemotherapy using the FOLFOX regimen.

MATERIALS AND METHODS

Between January 2007 and July 2014, 54 patients diagnosed and pathologically-confirmed with advanced colorectal cancer in Jiangsu Cancer Hospital and Research Institute, were enrolled. They received pemetrexed at a dose of 500mg/m2 by 10 minute infusion on day 1, repeated every 3 weeks. Doses were modified depending on nadir counts of blood cells. Combined chemotherapeutic agents included irinotecan, lobaplatin, carboplatin, oxaliplatin, gemcitabine, cis-platinum or bevacizumab. Multiple variables (age, sex, hemoglobin, platinum drugs combined, metastasis sites, LDH, ALP, CEA>40 ug/ml) reported earlier were selected.We used logistic regression analysis to evaluate relationships between these and tumor response.

RESULTS

On multivariable analysis, we found that age was significant in predicting the responsiveness to pemetrexed (p<0.05) combined with oxaliplatin. We did not find any other factors which were significantly associated with the response rate to chemotherapy with pemetrexed and irinotecan.

CONCLUSIONS

By multivariate analysis, we found that age had significant impact on the responsiveness of pemetrexed when combined with oxaliplatin. Additional research based on genomic properties of host and tumors are needed to clarify markers for better selection of patients who could benefit from pemetrexed combined chemotherapy.

Evaluation of stapled versus hand-sewn techniques for colo- rectal anastomosis after low anterior resection of mid-rectal carcinoma: a study on 50 patients

AIM

To evaluate the outcome of stapled versus sutured colo-rectal anastomosis after low anterior resection of mid-rectal carcinoma.

PATIENTS AND METHODS

A prospective study of fifty patients who underwent colo-rectal anastomosis following low anterior resection (LAR) of T2 mid-rectal cancers at the Egyptian National Cancer Institute during the time period from June 2010 to June 2013 was conducted. Classification was into two groups; a stapled anastomosis group I (25 patients) and a hand-sewn anastomosis group II (25 patients). All operations are evaluated regarding intra-operative complications such as anastomotic line bleeding, visceral injuries or major blood loss. The anastomotic time and operative time are documented for each operation. All patients are evaluated post-operatively for anastomotic leakage (AL), wound infection and ileus.

RESULTS

The distance of the tumor from the anal verge was 9.6 ± 2.0 cm in group I and 9.9 ± 2.4 cm in group II. The mean operative time was 191.5 ± 16.2 min in the stapled group and 208 ± 18.6 min in the sutured group (p=0.002). The mean anastomotic times were 9.0 ± 1.9 min and 19.7 ± 12.2 min (p=0.001). Anastomotic leakage developed in three (12.0%) patients in the stapled group and in four (16.0%) patients in the sutured group (p=1.000). Post-operative ileus was observed in 3 patients in group I and one patient in group II. Wound infection developed in three (12.0%) patients in the stapled group and four (16.0%) patients in the sutured group (p=1.000).

CONCLUSION

Colo-rectal anastomosis after low anterior resection for mid rectal carcinoma can be conducted safely either by stapling or hand-sewn techniques; however the stapling technique showed shorter anastomotic and operative times with no significant advantages regarding intra- or post-operative complications or hospital stay.

Comparison of efficacy and toxicity of first line chemotherapy with or without epirubicin for patients with advanced stage soft tissue sarcoma

PURPOSE

To compare the safety and efficacy of first-line chemotherapy regimen with or without doxorubicin in treating patients with advanced soft tissue sarcoma (STS).

PATIENTS AND METHODS

We retrospectively analyzed a cohort of 56 patients histologically confirmed with STS who were treated at Jiangsu Cancer Hospital and Research Institute from July 2011 to June 2012.The basic element of first line chemotherapy contained epirubicin in group B and lacked epirubicin in group A. Response was assessed using RECIST criteria. The Kaplan-Meier method was used to estimate progress free survival (PFS).

RESULTS

According to RECIST criteria , patients in group treated by chemotherapy without epirubicin, the objective response (OR) ratio was 6.5 % (CR0%+PR6.5%). Disease control rate (DCR=CR+PR+SD) was 25.8% with a median follow-up of 14.6 months, including 2 patients achieving a partial response (PR 6.5%) and a stable response (SD 19.4%) in 6. In group B with epirubicin based regimens, no patient had complete response, PR (28 %) was observed in 7 and SD (24 %) in 6. DCR was observed in 13 patients (52%). By Fisher's exact test, the DCR difference between the two groups was statistically significant (p=0.046). In group A, median PFS was 3.0 months (95%CI:2.1-3.8), compared with 4.0 months (95% CI:3.03- 4.97) in group B (p=0.0397 by log-rank test). Epirubicin based chemotherapy and ECOG performance status 0-1 were identified as favorable factors for progression in our cohort of patients. Differences of nonhematologic and hematologic toxicities were not statistically significant between the two groups, and the addition of epirobicin was not associated with cardiac toxicity (p=0.446).

CONCLUSION

Our study demonstrates that epirubicin-based chemotherapy is effective and well tolerated, and is superior to chemotherapy without epirubicin regarding efficacy. Therefore it is recommended that epirubicin-based chemotherapy should be considered as first line for patients with advanced STS.

Outcomes based on risk assessment of anastomotic leakage after rectal cancer surgery

PURPOSE

Anastomotic leakage (AL) is associated with high morbidity and mortality, high reoperation rates, and increased hospital length of stay. Here we investigated the risk factors for AL after anterior resection for rectal cancer with a double stapling technique.

PATIENTS AND METHODS

Data for 460 patients who underwent primary anterior resection with a double stapling technique for rectal carcinoma at a single institution from 2003 to 2007 were prospectively collected. All patients experienced a total mesorectal excision (TME) operation. Clinical AL was defined as the presence of leakage signs and confirmed by diagnostic work-up according to ICD-9 codes 997.4, 567.22 (abdominopelvic abscess), and 569.81 (fistula of the intestine). Univariate and logistic regression analyses of 20 variables were undertaken to determine risk factors for AL. Survival was analysed using the Cox regression method.

RESULTS

AL was noted in 35 (7.6%) of 460 patients with rectal cancer. Median age of the patients was 65 (50-74) and 161 (35%) were male. The diagnosis of AL was made between the 6th and 12th postoperative day (POD; mean 8th POD). After univariate and multivariate analysis, age (p=0.004), gender (p=0.007), tumor site (p<0.001), preoperative body mass index (BMI) (p<0.001), the reduction of TSGF on 5th POD less than 10U/ml (p=0.044) and the pH value of pelvic dranage less than or equal to 6.978 on 3rd POD (p<0.001) were selected as 6 independent risk factors for AL. It was shown that significant differences in survival of the patients were AL-related (p<0.001), high ASA score related (p=0.036), high-level BMI related (p=0.007) and advanced TNM stage related (p<0.001).

CONCLUSIONS

AL after anterior resection for rectal carcinoma is related to advanced age, low tumor site, male sex, high preoperative BMI, low pH value of pelvic drainage on POD 3 and a significant reduction of TSGF on POD 5. In addition to their high risk of immediate postoperative morbidity and mortality, AL, worse physical status, severe obesity and advanced TNM stage have similarly negative impact on survival.

Role of MYH polymorphisms in sporadic colorectal cancer in China: a case-control, population-based study

PURPOSE

Biallelic germline variants of the 8-hydroxyguanine (8-OG) repair gene MYH have been associated with colorectal neoplasms that display somatic G:C?T:A transversions. However, the effect of single germline variants has not been widely studied, prompting the present investigation of monoallelic MYH variants and susceptibility to sporadic colorectal cancer (CRC) in a Chinese population.

PATIENTS AND METHODS

Between January 2006 and December 2012, 400 cases of sporadic CRC and 600 age- and sex-matched normal blood donors were screened randomly for 7 potentially pathogenic germline MYH exons using genetic testing technology. Variants of heterozygosity at the MYH locus were assessed in both sporadic cancer patients and healthy controls. Univariate and multivariate analyses were performed to determine risk factors for cancer onset.

RESULTS

Five monoallelic single nucleotide polymorphisms (SNPs) were identified in the 7 exon regions of MYH, which were detected in 75 (18.75%) of 400 CRC patients as well as 42 (7%) of 600 normal controls. The region of exon 1 proved to be a linked polymorphic region for the first time, a triple linked variant including exon 1-316 G?A, exon 1-292 G?A and intron 1+11 C?T, being identified in 13 CRC patients and 2 normal blood donors. A variant of base replacement, intron 10-2 A?G, was identified in the exon 10 region in 21 cases and 7 controls, while a similar type of variant in the exon 13 region, intron 13+12 C?T, was identified in 8 cases and 6 controls. Not the only but a newly missense variant in the present study, p. V463E (Exon 14+74 T?A), was identified in exon 14 in 6 patients and 1 normal control. In exon 16, nt. 1678-80 del GTT with loss of heterozygosity (LOH) was identified in 27 CRC cases and 26 controls. There was no Y165C in exon 7 or G382D in exon 14, the hot- spot variants which have been reported most frequently in Caucasian studies. After univariate analysis and multivariate analysis, the linked variant in exon 1 region (p=0.002), intron 10-2 A?G (p=0.004) and p. V463E (p=0.036) in the MYH gene were selected as 3 independent risk factors for CRC.

CONCLUSIONS

According to these results, the linked variant in Exon 1 region, Intron 10-2 A?G of base replacement and p. V463E of missense variant, the 3 heterozygosity variants of MYH gene in a Chinese population, may relate to the susceptibility to sporadic CRC. Lack of the hot-spot variants of Caucasians in the present study may due to the ethnic difference in MYH gene.