[Analysis of influencing factors and clinical value of anterior peritoneal reflection for patients with rectal cancer].

Objectives: To investigate the factors influencing the height of anterior peritoneal reflection (APR) for patients with rectal cancer, and to analyze the relationship between the APR and the lateral lymph node metastasis. Methods: Clinical data of 432 patients with tumor located within and below APR were retrospectively collected from the rectal cancer database at the Department of General Surgery, Peking Union Medical College Hospital from August 2020 to September 2022. Ninty-eight non-rectal cancer patients were also enrolled as a control group. There were 308 males and 124 females in the tumor group, aged (M(IQR)) 62 (16) years (range: 24 to 85 years) and 53 males and 45 females in the control group, aged 60 (22) years (range: 27 to 87 years). The APR height, pelvis, and tumor-related parameters were measured by MRI. A multifactor linear regression model was established to analyze the dependent correlation factors of APR height. These factors of the two groups were matched by propensity score matching and their APR heights were compared after matching. An ordinal Logistic regression model was established to explore the relationship between APR-related parameters and radiographic lateral lymph node metastasis. Results: The APR height of the tumor group was (98.7±14.4) mm (range: 43.3 to 154.0 mm) and the control group was (95.1±12.7) mm (range: 68.0 to 137.9 mm). Multivariable linear regression revealed that the greater the weight (B=0.519, 95%CI: 0.399 to 0.640, P<0.01), the anterior pelvic depth (B=0.109, 95%CI: 0.005 to 0.213, P=0.039) and the smaller the bi-ischial diameter (B=-0.172, 95%CI:-0.294 to -0.049, P=0.006), the higher the APR height. The tumor group had a higher APR height than the control group after propensity score matching ((98.3±14.2) mm vs. (95.1±12.7) mm, t=-1.992, P=0.047). Ordinal Logistic regression indicated that the longer segment of the tumor invade the nonperitoneal rectum was an independent influencing factor of radiographic lateral lymph node metastasis (OR=1.016, 95%CI: 1.002 to 1.030, P=0.021), while the distance between the anal verge and the tumor was not (OR=0.986, 95%CI: 0.972 to 1.000, P=0.058). Conclusions: The higher the weight, the deeper and narrower the pelvis, the higher the APR height. There is a certain relationship between APR and lateral lymph node metastasis on imaging.

[Clinicopathological characteristics, diagnosis, and treatment of 29 cases of signet ring cell carcinoma of the rectum and sigmoid colon].

Objective: To investigate the clinicopathological characteristics and the therapeutic effects of signet ring cell carcinoma (SRCC) of rectum and sigmoid colon. Methods: Clinical data and the follow-up information of 29 SRCC patients treated in our tertiary care center from 2008 to 2018 were retrospectively reviewed. The clinicopathological features, diagnostic and therapeutic effects, and the prognostic outcomes were analyzed. Results: Among the 29 patients, 17 were male, 12 were female. The average age was (48.7±14.3) years. Colonoscopy revealed the features of diffuse circumferential thickening of the bowel wall in 20/29 cases (69.0%), while in 9/29 cases (31.0%), endoscopic biopsies showed false negative results. Twenty-five% (4/16) and 17.6% (3/17) lesions were misdiagnosed as the inflammatory changes by endoscopic rectal ultrasonography exam and rectal MRI scan, respectively. Thirteen of the 29 patients received the neoadjuvant chemoradiotherapy (NCRT), 27 patients underwent the radical resection surgeries, and 8 underwent the postoperative radiotherapy. With a median follow-up of 38.5 (3.5-87.0) months, the cumulative 3-years overall survival (OS) rate was 54.0%, and the cumulative 3-years disease-free survival (DFS) rate was 43.0%. The OS rates of patients treated with or without NCRT (non-NCRT) were 46.2% and 69.2%, respectively, without significant difference (P>0.05). The DFS rates of patients treated with or without NCRT were 45.8% and 39.2%, respectively, without significant difference (P>0.05). Parameters including age younger than 40 years and tumor size larger than 5 cm were independent potential risk factors for shortened OS (P<0.05). Conclusions: SRCC of the rectum and sigmoid colon is a rare malignant tumor with special clinical manifestations. It is younger-onset, highly malignant and with very poor prognosis. Therefore, in-depth researches with focus upon the progress of molecular oncology are urgently needed to substantially improve the therapeutic effect of this disease.

Phylogenetic relationships of twenty Gymnothorax species based on cytochrome b sequence data.

To study the phylogenetic relationships of the genus Gymnothorax (moray eels) distributed in South China Sea, polymerase chain reactions were performed, and the amplification products were sequenced by cloning into the PMD18T-vector (TaKaRa). The entire gene sequences encoding cytochrome b (1140 bp) for 16 Gymnothorax (G. flavimarginatus, G. meleagris, G. undulates, G. reticularis, G. reevesi, G. melanospilus, G. rueppeliae, G. javanicus, G. chilospilus, G. pseudothyrsoideus, G. fimbriatus, G. hepaticus, G. berndti, G. curostus, G. favagineus, and G. margaritophorus) were obtained. Four additional Gymnothorax sequences from GenBank were also included. The nucleotide composition, genetic distances, and base substitution saturation analysis were calculated using the MEGA 5.0 Software. Phylogenetic analysis was performed using maximum-parsimony, maximum-likelihood (ML), and neighbor-joining (NJ). The results were as follows: 1) base-substitution saturation analysis suggested that both in third codon positions, and the full-length cytochrome b data set, Ts are not saturated, but Tv substitutions may be saturated, 2) the genus Gymnothorax, native to the South China Sea, is divided into four distinct clades, with two clades in the NJ and ML trees, and 3) according to our experimental data, G. melanospilus (Bleeker, 1855) and G. favagineus (Bloch and Schneider, 1801) are the same species.

MicroRNA-219-5p functions as a tumor suppressor partially by targeting platelet-derived growth factor receptor alpha in colorectal cancer.

Platelet-derived growth factor receptor (PDGFR) signaling pathway was involved in the progress of colorectal cancer (CRC). By using the bioinformatic system online, we found that PDGFRα is a potential target of miR-219-5p. However, the expression pattern and underlying mechanisms of miR-219-5p had not been elucidated in CRC. Herein, we first evaluated the expression of miR-219-5p in tumor tissues by real-time polymerase chain reaction. Next, we confirmed that PDGFRα is the target of miR-219-5p by using luciferase report. And then, we investigated the biological functions of miR-219-5p in vitro in cell proliferation and apoptosis as well as cell cycle by gain and loss of function strategies. Data shown that miR-219-5p is down-regulated in CRC tissues compared with the corresponding matched normal tissues. PDGFRα was a direct target of miR-219-5p. Overexpression of miR-219-5p could inhibit cell proliferation, promote cell apoptosis and induce cell cycle arrest at the G1 phase. Furthermore, miR-219-5p suppressed the activation of the phosphatidylinositol 3-kinase/Akt signaling pathway and downregulated G1 cell-cycle-related protein cyclin D1, cyclin-dependent kinase (CDK) 4, and CDK6. Taken together, our results demonstrate that miR-219-5p functions as a tumor suppressor partially by targeting PDGFRα in colorectal cancer.

Isolation and characterization of polymorphic microsatellite markers in Bagarius yarrelli using RNA-Seq.

The yellow sisorid catfish (Bagarius yarrelli) is a vulnerable fish species. In this study, seven polymorphic microsatellite DNA markers for yellow sisorid catfish were described, using RNA-Seq methodology. In B. yarrelli (N = 44) from a Hekou wild population, allelic frequency, and observed and expected heterozygosities per locus varied from two to six, 0.0333 to 0.6793, and 0.0333 to 0.6004, respectively. One locus (Baya153) denoted notable separation from the Hardy-Weinberg equilibrium, after sequential Bonferroni correction (P < 0.05). The microsatellite markers described here will be useful for investigating population structure and genetic resource of B. yarrelli from different geographical locations.

[Effects of tumor location and mismatch repair on clinicopathological features and survival for non-metastatic colon cancer: A retrospective, single center, cohort study].

Objective: To analyze the differences in clinicopathological features of colon cancers and survival between patients with right- versus left-sided colon cancers. Methods: This was a retrospective cohort study. Information on patients with colon cancer from January 2016 to August 2020 was collected from the prospective registry database at Peking Union Medical College Hospital . Primary tumors located in the cecum, ascending colon, and proximal two-thirds of the transverse colon were defined as right-sided colon cancers (RCCs), whereas primary tumors located in the distal third of the transverse colon, descending colon, or sigmoid colon were defined as left-sided colon cancers (LCCs). Clinicopathological features were compared using the χ2 test or Mann-Whitney U test. Survival was estimated by Kaplan-Meier curves and the log-rank test. Factors that differed significantly between the two groups were identified by multivariate survival analyses performed with the Cox proportional hazards function. One propensity score matching was performed to eliminate the effects of confounding factors. Results: The study cohort comprised 856 patients, with TNM Stage I disease, 391 (45.7%) with Stage II, and 336 (39.3%) with Stage III, including 442 (51.6%) with LCC and 414 (48.4%) with RCC and 129 (15.1%). Defective mismatch repair (dMMR) was identified in 139 patients (16.2%). Compared with RCC, the proportion of men (274/442 [62.0%] vs. 224/414 [54.1%], χ2=5.462, P=0.019), body mass index (24.2 [21.9, 26.6] kg/m2 vs. 23.2 [21.3, 25.5] kg/m2, U=78,789.0, P<0.001), and well/moderately differentiated cancer (412/442 [93.2%] vs. 344/414 [83.1%], χ2=22.266, P<0.001) were higher in the LCC than the RCC group. In contrast, the proportion of dMMR (40/442 [9.0%] vs. 99/414 [23.9%], χ2=34.721, P<0.001) and combined vascular invasion (106/442[24.0%] vs. 125/414[30.2%], χ2=4.186, P=0.041) were lower in the LCC than RCC group. The median follow-up time for all patients was 48 (range 33, 59) months. The log-rank test revealed no significant differences in disease-free survival (DFS) (P=0.668) or overall survival (OS) (P=0.828) between patients with LCC versus RCC. Cox proportional hazards model showed that dMMR was significantly associated with a longer DFS (HR=0.419, 95%CI: 0.204‒0.862, P=0.018), whereas a higher proportion of T3-4 (HR=2.178, 95%CI: 1.089‒4.359, P=0.028), N+ (HR=2.126, 95%CI: 1.443‒3.133, P<0.001), and perineural invasion (HR=1.835, 95%CI: 1.115‒3.020, P=0.017) were associated with poor DFS. Tumor location was not associated with DFS or OS (all P>0.05). Subsequent analysis showed that RCC patients with dMMR had longer DFS than did RCC patients with pMMR (HR=0.338, 95%CI: 0.146‒0.786, P=0.012). However, the difference in OS between the two groups was not statistically significant (HR=0.340, 95%CI:0.103‒1.119, P=0.076). After propensity score matching for independent risk factors for DFS, the log-rank test revealed no significant differences in DFS (P=0.343) or OS (P=0.658) between patients with LCC versus RCC, whereas patient with dMMR had better DFS (P=0.047) and OS (P=0.040) than did patients with pMMR. Conclusions: Tumor location is associated with differences in clinicopathological features; however, this has no impact on survival. dMMR status is significantly associated with longer survival: this association may be stronger in RCC patients.

[Safety and prognosis analysis of transanal total mesorectal excision versus laparoscopic mesorectal excision for mid-low rectal cancer].

Objective: To compare the short-term and long-term outcomes between transanal total mesorectal excision (taTME) and laparoscopic total mesorectal excision (laTME) for mid-to-low rectal cancer and to evaluate the learning curve of taTME. Methods: This study was a retrospective cohort study. Firstly, consecutive patients undergoing total mesorectal excision who were registered in the prospective established database of Division of Colorectal Diseases, Department of General Surgery, Peking Union Medical College Hospital during July 2014 to June 2020 were recruited. The enrolled patients were divided into taTME and laTME group. The demographic data, clinical characteristics, neoadjuvant treatment, intraoperative and postoperative complications, pathological results and follow-up data were extracted from the database. The primary endpoint was the incidence of anastomotic leakage and the secondary endpoints included the 3-year disease-free survival (DFS) and the 3-year local recurrence rate. Independent t-test for comparison between groups of normally distributed measures; skewed measures were expressed as M (range). Categorical variables were expressed as examples (%) and the χ(2) or Fisher exact probability was used for comparison between groups. When comparing the incidence of anastomotic leakage, 5 variables including sex, BMI, clinical stage evaluated by MRI, distance from tumor to anal margin evaluated by MRI, and whether receiving neoadjuvant treatment were balanced by propensity score matching (PSM) to adjust confounders. Kaplan-Meier curve and Log-rank test were used to compare the DFS of two groups. Cox proportional hazard model was used to analyze and determine the independent risk factors affecting the DFS of patients with mid-low rectal cancer. Secondly, the data of consecutive patients undergoing taTME performed by the same surgical team (the trananal procedures were performed by the same main surgeon) from February 2017 to March 2021 were separately extracted and analyzed. The multidimensional cumulative sum (CUSUM) control chart was used to draw the learning curve of taTME. The outcomes of 'mature' taTME cases through learning curve were compared with laTME cases and the independent risk factors of DFS of 'mature' cases were also analyzed. Results: Two hundred and forty-three patients were eventually enrolled, including 182 undergoing laTME and 61 undergoing taTME. After PSM, both fifty-two patients were in laTME group and taTME group respectively, and patients of these two groups had comparable characteristics in sex, age, BMI, clinical tumor stage, distance from tumor to anal margin by MRI, mesorectal fasciae (MRF) and extramural vascular invasion (EMVI) by MRI and proportion of receiving neoadjuvant treatment. After PSM, as compared to laTME group, taTME group showed significantly longer operation time [(198.4±58.3) min vs. (147.9±47.3) min, t=-4.321, P<0.001], higher ratio of blood loss >100 ml during surgery [17.3% (9/52) vs. 0, P=0.003], higher incidence of anastomotic leakage [26.9% (14/52) vs. 3.8% (2/52), χ(2)=10.636, P=0.001] and higher morbidity of overall postoperative complications [55.8%(29/52) vs. 19.2% (10/52), χ(2)=14.810, P<0.001]. Total harvested lymph nodes and circumferential resection margin involvement were comparable between two groups (both P>0.05). The median follow-up for the whole group was 24 (1 to 72) months, with 4 cases lost, giving a follow-up rate of 98.4% (239/243). The laTME group had significantly better 3-year DFS than taTME group (83.9% vs. 73.0%, P=0.019), while the 3-year local recurrence rate was similar in two groups (1.7% vs. 3.6%, P=0.420). Multivariate analysis showed that and taTME surgery (HR=3.202, 95%CI: 1.592-6.441, P=0.001) the postoperative pathological staging of UICC stage II (HR=13.862, 95%CI:1.810-106.150, P=0.011), stage III (HR=8.705, 95%CI: 1.104-68.670, P=0.040) were independent risk factors for 3-year DFS. Analysis of taTME learning curve revealed that surgeons would cross over the learning stage after performing 28 cases. To compare the two groups excluding the cases within the learning stage, there was no significant difference between two groups after PSM no matter in the incidence of anastomotic leakage [taTME: 6.7%(1/15); laTME: 5.3% (2/38), P=1.000] or overall complications [taTME: 33.3%(5/15), laTME: 26.3%(10/38), P=0.737]. The taTME was still an independent risk factor of 3-year DFS only analyzing patients crossing over the learning stage (HR=5.351, 95%CI:1.666-17.192, P=0.005), and whether crossing over the learning stage was not the independent risk factor of 3-year DFS for mid-low rectal cancer patients undergoing taTME (HR=0.954, 95%CI:0.227-4.017, P=0.949). Conclusions: Compared with conventional laTME, taTME may increase the risk of anastomotic leakage and compromise the oncological outcomes. Performing taTME within the learning stage may significantly increase the risk of postoperative anastomotic leakage.

[Risk factors of postoperative surgical site infection in colon cancer based on a single center database].

Objective: To explore the incidence and risk factors of postoperative surgical site infection (SSI) after colon cancer surgery. Methods: A retrospective case-control study was performed. Patients diagnosed with colon cancer who underwent radical surgery between January 2016 and May 2021 were included, and demographic characteristics, comorbidities, laboratory tests, surgical data and postoperative complications were extracted from the specialized prospective database at Department of General Surgery, Peking Union Medical College Hospital. Case exclusion criteria: (1) simultaneously multiple primary colon cancer; (2) segmental resection, subtotal colectomy, or total colectomy; (3) patients undergoing colostomy/ileostomy during the operation or in the state of colostomy/ileostomy before the operation; (4) patients receiving natural orifice specimen extraction surgery or transvaginal colon surgery; (5) patients with the history of colectomy; (6) emergency operation due to intestinal obstruction, perforation and acute bleeding; (7) intestinal diversion operation; (8) benign lesions confirmed by postoperative pathology; (9) patients not following the colorectal clinical pathway of our department for intestinal preparation and antibiotic application. Univariate analysis and multivariate analysis were used to determine the risk factors of SSI after colon cancer surgery. Results: A total of 1291 patients were enrolled in the study. 94.3% (1217/1291) of cases received laparoscopic surgery. The incidence of overall SSI was 5.3% (69/1291). According to tumor location, the incidence of SSI in the right colon, transverse colon, left colon and sigmoid colon was 8.6% (40/465), 5.2% (11/213), 7.1% (7/98) and 2.1% (11/515) respectively. According to resection range, the incidence of SSI after right hemicolectomy, transverse colectomy, left hemicolectomy and sigmoid colectomy was 8.2% (48/588), 4.5% (2/44), 4.8% (8 /167) and 2.2% (11/492) respectively. Univariate analysis showed that preoperative BUN≥7.14 mmol/L, tumor site, resection range, intestinal anastomotic approach, postoperative diarrhea, anastomotic leakage, postoperative pneumonia, and anastomotic technique were related to SSI (all P<0.05). Multivariate analysis revealed that anastomotic leakage (OR=22.074, 95%CI: 6.172-78.953, P<0.001), pneumonia (OR=4.100, 95%CI: 1.546-10.869, P=0.005), intracorporeal anastomosis (OR=5.288, 95%CI: 2.919-9.577,P<0.001) were independent risk factors of SSI. Subgroup analysis showed that in right hemicolectomy, the incidence of SSI in intracorporeal anastomosis was 19.8% (32/162), which was significantly higher than that in extracorporeal anastomosis (3.8%, 16/426, χ(2)=40.064, P<0.001). In transverse colectomy [5.0% (2/40) vs. 0, χ(2)=0.210, P=1.000], left hemicolectomy [5.4% (8/148) vs. 0, χ(2)=1.079, P=0.599] and sigmoid colectomy [2.1% (10/482) vs. 10.0% (1/10), χ(2)=2.815, P=0.204], no significant differences of SSI incidence were found between intracorporeal anastomosis and extracorporeal anastomosis (all P>0.05). Conclusions: The incidence of SSI increases with the resection range from sigmoid colectomy to right hemicolectomy. Intracorporeal anastomosis and postoperative anastomotic leakage are independent risk factors of SSI. Attentions should be paid to the possibility of postoperative pneumonia and actively effective treatment measures should be carried out.