Tumor heterogeneity is one of the characteristics of malignant tumors, which refers to the molecular biology or genetic changes in the daughter cells of tumors after multiple division and proliferation during the growth process, resulting in changes in tumor growth rate, invasion ability, drug sensitivity, and prognoses. Pituitary adenomas (PAs) are generally considered as benign tumors without obvious heterogeneity, but the identification of reliable heterogeneity markers still plays a key role in clinical diagnosis and treatment. In clinical practice, the heterogeneity of parenchymal PAs includes differences in imaging findings, histopathological findings, and molecular information. This article reviews the research results in PAs heterogeneity so as to provide better enlightenment for clinical research and practice.

Colorectal cancer is one of the most common malignant tumors of digestive tract. In 2020， 1.93 million new cases of colorectal cancer were diagnosed globally， ranking third in the global incidence spectrum， and 930 000 new deaths were reported， ranking second in the global cause of death spectrum. Meanwhile， the medical cost of metastatic colorectal cancer is the highest among all stages. A large number of studies have demonstrated that traditional Chinese medicine（TCM） treatment can bring clinical benefits to patients with metastatic colorectal cancer with unique efficacy. In order to further standardize the TCM diagnosis and treatment for metastatic colorectal cancer and improve the level of TCM diagnosis and treatment， Xiyuan Hospital， China Academy of Chinese Medical Sciences， together with other relevant units in China， according to the guideline development process of the World Health Organization Handbook for Guideline Development and the relevant requirements of the Clinical Evidence Grading Criteria on TCM Based on Evidence Body， the Regulations for Group Standards of China Association of Chinese Medicine and others， combined with the characteristics of TCM diagnosis and treatment and the actual situation in China， the Guidelines for TCM Diagnosis and Treatment of Metastatic Colorectal Cancer was developed in accordance with the Catalogue of TCM Diagnosis and Treatment Plans for 105 Diseases in 24 Specialties issued by Department of Medical Administration of National Administration of TCM.

RAS, a member of the small GTPase family, functions as a binary switch by shifting between inactive GDP-loaded and active GTP-loaded state. RAS gain-of-function mutations are one of the leading causes in human oncogenesis, accounting for ∼19% of the global cancer burden. As a well-recognized target in malignancy, RAS has been intensively studied in the past decades. Despite the sustained efforts, many failures occurred in the earlier exploration and resulted in an 'undruggable' feature of RAS proteins. Phosphorylation at several residues has been recently determined as regulators for wild-type and mutated RAS proteins. Therefore, the development of RAS inhibitors directly targeting the RAS mutants or towards upstream regulatory kinases supplies a novel direction for tackling the anti-RAS difficulties. A better understanding of RAS phosphorylation can contribute to future therapeutic strategies. In this review, we comprehensively summarized the current advances in RAS phosphorylation and provided mechanistic insights into the signaling transduction of associated pathways. Importantly, the preclinical and clinical success in developing anti-RAS drugs targeting the upstream kinases and potential directions of harnessing allostery to target RAS phosphorylation sites were also discussed.

Objective:To analyze the clinicopathological features and prognostic factors of alpha‐fetoprotein‐producing gastric carcinoma (AFPGC).Methods:A retrospective analysis was made on 2 671 GC patients admitted from Jan 1998 to Dec 2018 , AFPGC patients and matching AFP negative GC cases were enrolled and their clinicopathological features and prognostic factors were analyzed. The survival curve was drawn by Kaplan-Meier method. Log-rank test was used to test the significance, Univariate analysis was performed by using COX proportional hazard model.Results:There were 98 AFPGC in this study accounting for 4.5% of all GC of the corresponding time period. The proportion of male to female was 2.16∶1, the average age was (65±12) years. The serum AFP levels significantly decreased after operation in most patients (median: 52 ng/ml vs. 5 ng/ml, Ｚ=-2.736, P=0.001). Serum AFP and CEA levels in patients with AFPGC before treatment were significantly higher than that in patients with AFP negative GC (both P<0.05) . Vascular invasion(62.71% vs. 40.68%) and liver metastasis (31.63% vs .6.12%) were more likely to occur in AFPGC groups (both P<0.05). However, there was no significant difference between the two groups in tumor size, location, differentiation and lymph node metastasis (all P>0.05). The prognosis of AFPGC was significant pooer than that in AFP negative GC ( P<0.05). Prognosis of AFPGC patients was significantly correlated with preoperative serum AFP level, TNM stage, lymph node metastasis, simultaneous liver metastasis and vascular invasion (all P<0.05) . COX multivariate survival analysis found that preoperative serum AFP level was independent risk factors of patients with AFPGC ( P<0.05). Conclusion:AFPGC is a special GC charactering poor prognosis .

Objective:To study the relation ship between the branch patterns of inferior mesenteric artery (IMA) and imaging pelvic measurement parameters for anastomotic leakage (AL) after anterior resection (AR) of rectal cancer.Methods:Five hundred thirty-four patient were enrolled from Jan 2008 to Dec 2018 at the General Surgery Department of Guizhou Provincial People's Hospital. The AL related imaging risk factors were analyzed by chi-square test or Fisher's exact test.Results:AL was found in 36 (6.7%) patients. AL related mortality rate was 11.1% (4/36) compared to 0.4% (2/498) in those without the complications of no AL cases ( P<0.001). Seven pelvic imaging measurement results were attained in 412 patients including anteroposterior diameter of the inlet of the pelvis, anteroposterior diameter of the outlet of the pelvis, upper edge of the symphysis pubis to the tip of the coccyx, sacrococcygeal distance angle from the lower edge of the pubis to the upper edge of the pubis to the sacral promontory, distance between the ischial spines and that of ischial tuberosity. Univariate analysis showed that there was no significant relationship between the above 7 pelvic measurement parameters and the occurrence of AL (all P>0.05). There was no significant relationship between branch patterns of IMA and AL after rectal cancer surgery ( P=0.712). Conclusion:AL as a severe postoperative complication in rectal cancer patients undergoing AR procedure were caused by multiple factors. Neither IMA branch patters nor pelvic imaging measurement seem to be related to the occurrence of AL after AR for rectal cancer.

Objective: To analyze anxiety and its influencing factors of medical college students during the epidemic of COVID-19, so as to provide theoretical basis for targeted mental health promotion. Methods: Participants were selected through convenient sampling in 2 medical colleges, and general situation questionnaires, anxiety self rating scale(SAS), were csuected through questionnaire stars among to 6 276 medical college students anonymously through online platforms such as WeChat and QQ during the COVID-19 epidemic. Results: SAS scores of medical students was(38.52±7.76), anxiety detection rate was 8.9%. Anxiety detection rate varied significantly by gender, the frequency of protection alerting by the counselor, college level, residence, self reported health status, confirmed cases in the community, personal attention, disinfection, perceived risk of infection,as well as panic in the outbreak of COVID-19 (all P <0.05). Multivariate Logistic analysis showed that undergraduate( OR = 1.25 ), high perceived risk of infection( OR =1.71); extreme panic ( OR =2.75) were associated with high detection rate of anxiety. Female students( OR =0.62), rural residents( OR =0.80), moderate health status( OR =0.06), in good health( OR =0.11), in excellent health( OR =0.30); know or don t know there were COVID-19 patients in their residential areas( OR =0.67), close attention to COVID-19 1-2 times/d( OR = 0.47 ), or frequently( OR =0.38); moderate inevitable disinfection( OR =0.53), few inevitable disinfection ( OR =0.32) were associated with low detection rate of anxiety. Conclusion During the epidemic of COVID-19, anxiety among the medical college students was high, which varies by gender and college level. Psychological adjustment, appropriate attention and positive attitude towards COVID-19 should be promoted among medical college students. School counsellors should pay more attention and care to students while providing COVID-19 information through various ways.

OBJECTIVETo explore the feasibility and clinical significance of precision low inferior mesenteric artery (IMA) ligation with the left colonic artery (LCA) preservation and root lymph node dissection in laparoscopic radical resection for rectal cancer, according to the inferior mesenteric artery (IMA) types.

METHODSOne Hundred and fore cases of rectal cancer patients who underwent laparoscopic resection in The Sixth Affiliated Hospital of Sun Yat-sen University from October 2015 to June 2016 were selected and divided into study group and control group according to different surgical methods. The study group (52 cases) accepted precision low IMA ligation with the LCA preservation and root lymph node (No.253) dissection, according to the IMA types and length examined by preoperative computed tomography angiography (CTA) reconstruction. The control group (52 cases) accepted the traditional high IMA ligation. The perioperative efficacy indexes and postoperative recovery situation of the two groups were compared.

RESULTSThe IMA types, IMA length and preoperative clinical stages were not significantly different between the two groups (all P>0.05). The surgery was completed smoothly for patients in both groups, with no conversion to open surgery. But two patients in the study group underwent left colonic artery ligation for intra-operative need. There were no significant differences in the operative time, intra-operative blood lose, the rate of protective ileostomy and post-operative pathological stages between the two groups (all P>0.05). More total lymph nodes [(24.9±5.7) vs. (16.9±4.2), P=0.001] and No.253 lymph nodes [(2.4±1.1) vs. (1.5±0.8), P=0.001] were harvested in study group as compared to control group. However, the positive rate of total harvested lymph nodes and No.253 lymph nodes between the two groups were not significantly different (P>0.05). There were no significant differences between the two groups in postoperative first anal exhaust time, postoperative hospital stay, total volume of postoperative intraperitoneal drainage, postoperative abdominal drainage tube retention time, postoperative anal drainage tube retention time and postoperative catheter retention time (All P>0.05). There were 2 cases of postoperative dysuria and 1 case of anastomotic bleeding in study group. There were 3 cases of postoperative dysuria and 2 cases of anastomotic leak in control group. Less postoperative complications (5.8% vs. 9.6%, P<0.05) in study group as compared to control group. There was no rehospitalization or death case in two groups within 30 days after operation.

CONCLUSIONSIn the laparoscopic radical resection of rectal cancer, preserving LCA and cleaning the root lymph nodes according to IMA types, which could increase the number of harvested lymph nodes and reduce the postoperative complications was safe and effective.

Objective To explore the effects of premature atrial contractions on hemodynamics combined with coronary heart disease and hypertension .Methods According to the advance rate ,62 patients with premature atrial contractions were invided into 3 groups :< 20% group(n= 18) ,20% - 40% group(n= 20) and > 40% group(n= 24) .All of the patients were performed imped‐ance cardiography .The hemodynamics indexes at different times were compared ,and the variation rates in hemodynamics of the three groups combined with basic diseases were analyzed .Results Stroke volume(SV) ,stroke index(SI) ,aortic compliance(AC) , stroke work(SW) ,stroke work index(SWI) ,and heather index(HI) were smallest when premature atrial contractions ,which were middle when the first sinus beats before premature atrial contractions ,and largest when the first sinus beats after premature atrial contractions(P< 0 .05) .The variation rates in hemodynamics were smallest in < 20% group ,which were middle in 20% - 40%group ,and largest in > 40% group(P< 0 .05) .The percentage of patients with basic heart diseases was lowest in < 20% group , which was middle in 20% - 40% group ,and highest in > 40% group(P< 0 .05) .Conclusion The advance rate is relatively large in patients with basic cardiovascular disease .Premature atrial contractions has certain effects on hemodynamics ,and the effects are positively correlated with advance rate .

Objective To study the development characteristics of cavum sepit pellucidun (CSP)in prematures,neonates,infants and adults with MRI.Methods Brain MR images of different subjects including 141 prematures,106 neonates,171 infants and 35 046 adults were observed to determine the incidence and shape of CSP,and to measure its transverse diameter.Results CSP incidences were 100% (141/141)in prematures,97.17% (103/106)in neonates,2.26%(4/177)in infants and 0.82% (287/35 046)in adults respectively,and the CSP was cylinder (44.00%)or triangle in shape (56.00%)in prematures,triangle (76.40%)or fissure in shape (23.60%)in neonates.For infants or adults,each shape accounted for about a third of three kinds of shape respectively.Its mean transverse diameters were 5.7 mm in prematures,4.1 mm in neonates,13.3 mm in infants and 14.3 mm in adults respectivity.Conclusion CSP has different performances at development periods in human being brain.Most close after birth,while fewer remain in the whole life.

OBJECTIVETo compare the safety and efficacy of the medial approach(MA) and the lateral approach (LA) in the treatment of colorectal disease.

METHODSStudies published from January 1994 to April 2013 that compared MA to LA in laparoscopic colorectal resection were collected. Publications in English were mainly identified from Medline, Embase, Cochrane Library, and those in Chinese from Wanfang database and CNKI database. Conversion rate, operative time, blood loss, number of harvested lymph nodes, hospital stay, complication, mortality, recurrence, and hospitalization costs of MA and LA were meta-analyzed using fixed-effect and random-effect models.

RESULTSFive cohort studies (2 randomized controlled trials and 3 retrospective studies) including 881 patients were enrolled and analyzed. Of these patients, 416 and 465 underwent laparoscopic colorectal resection with MA and LA respectively. As compared to LA, MA had significantly lower conversion rate (OR=0.42, 95%CI:0.25-0.72, P=0.001), shorter operative time (WMD=-52.62, 95%CI:-63.23--42.01, P<0.01), less number of harvested lymph nodes (WMD=-1.17, 95%CI:-1.89--0.45, P=0.001), while blood loss was less and hospitalization cost lower. Significant differences in intraoperative complications and postoperative complications were not found between the two group (OR:0.57, 95%CI:0.15-2.18, P=0.41; OR:0.78, 95%CI:0.52-1.17, P=0.23).

CONCLUSIONSCompared with LA, MA has the advantages of shorter operative time and lower conversion rate with similar safety. Differences in blood loss, hospitalization cost and oncological safety between the two approaches warrant further investigation.