| Background and ObjectivePrimary malignant tumor of appendix is a clinically very rare malignant tumor of the digestive tract,and its incidence is about 0.4%-1.0% of gastrointestinal malignant tumors.The main pathological types include appendix mucinous adenocarcinoma,appendicular colon adenocarcinoma,appendix carcinoid,and signet ring cell carcinoma.The clinical manifestations of PMTA are similar to those of acute or chronic appendicitis,mainly characterized by dull pain in the right lower quadrant,which is often misdiagnosed clinically.Therefore,most patients are in advanced stage when they are finally diagnosed.At present,the treatment of primary appendix malignant tumors mainly includes surgery and chemotherapy.The surgical procedures include simple appendectomy and righthemicolectomy.There is no standard chemotherapy regimen in PMTA.Currently,it is based on the chemotherapy regimen of colorectal cancer.PMTA is not sensitive to chemotherapy and has a poor prognosis.Therefore,it is urgent to explore new treatment methods and find new treatment modes.In recent years,the efficacy of cytotoxic drugs has progressed slowly,and the clinical benefits of targeting and immunotherapy have been increasing.In the whole management of malignant tumors,targeting and immunotherapy alone or in combination with radiotherapy and chemotherapy may bring more patients.Survival benefits.According to relevant literature,the incidence of high instability of colorectal cancer microsatellite is high,up to 15%,and the incidence of MSI-H in right half colorectal cancer is 20%,while hereditary nonpolyposis colorectal cancer(Lynch syndrome)occurs almost exclusively through the MSI pathway.Malignant tumors of the appendix are also tumors of the digestive tract.Due to the low incidence rate,the detection of the microsatellite status of the tumor is very rare,and the patients with highly unstable microsatellites cannot benefit from the chemotherapy of fluorouracil.Therefore,the detection of malignantness of the appendix is detected.The microsatellite state of the tumor is necessary.In recent years,with the in-depth study of molecular biology and tumor immune escape mechanism,the use of new molecular targets and immunological checkpoint inhibitors to treat malignant tumors has also become a research hotspot.At present,for intestinal tumors,the commonly detected targets include KRAS,BRAF,etc.,and targeted therapy can be guided according to whether the relevant target is mutated.By discussing the characteristics of the disease of primary appendix malignant tumor,this paper summarizes the characteristics of the disease,can improve the understanding of the disease,reduce the rate of misdiagnosis;explore the new treatment methods of appendix malignant tumor by detecting the status of KRAS,BRAF and MSI,Improve patient prognosis.Materials and Methods1.Retrospective analysis of clinical data of 55 patients with primary malignant tumors diagnosed by pathology from January 2010 to September 2018,including the first sex,age,first symptoms,pathology Type,tumor markers,abdominal Doppler ultrasound,abdominal spiral CT,surgical methods,chemotherapy regimens,prognosis,etc.2.Of the 55 patients with appendical malignant tumors,51 underwent surgery.Of these,16 were operated in external hospitals.The remaining 35 patients underwent surgery in our hospital.35 cases of pathological tissues were collected from the hospital.DNA of tumor tissues was extracted for KRAS and BRAF gene detection.Whether BRAF is mutated;extracting tumor tissue and normal tissue DNA,and detecting MSI status by multiplex PCR-capillary electrophoresis.ResultsOf the 55 patients with primary malignant tumors diagnosed by pathology,26 were male and 29 were female,aged between 8 and 80,with an average age of 54.7 years.The clinical symptoms are mainly abdominal pain and abdominal distension.Most patients had elevated tumor markers CEA,CA199,CA125 and CA724.Abdominal CT,abdominal color Doppler ultrasound and colonoscopy can help detect the lesion,and the final diagnosis depends on pathological examination.The pathological types of 55 patients with appendicitis were: 5 cases of appendix carcinoid(9.09%),34 cases of appendix mucinous adenocarcinoma(61.82%),13 cases of appendix colon adenocarcinoma(23.64%),signet ring cell carcinoma of the appendix.In the case of(5.45%),the proportion of mucinous adenocarcinoma of the appendix was the highest.Among the 35 patients with primary appendix malignant tumors with appendectomy,there were 24 cases of appendical mucinous adenocarcinoma,8 cases of colonic adenocarcinoma,1 case of carcinoid,and 2 cases of signet ring cell carcinoma.The pathological tissue DNA of 24 patients with appendical mucinous adenocarcinoma was extracted for KRAS and BRAF gene detection,and 8 patients developed KRAS gene mutation.The BRAF genes are all wild type.KRAS and BRAF genes were detected in 8 cases of appendix colonic adenocarcinoma tumor tissue.One patient developed KRAS gene mutation;8 patients had BRAF gene in wild type.The KRAS and BRAF genes of a case of appendix carcinoid were wild type.The KRAS and BRAF genes of 2 patients with signet ring cell carcinoma of the appendix were wild type.24 patients with appendicral mucinous adenocarcinoma underwent MSI.One patient had high microsatellite instability(MSI-H),one patient had low microsatellite instability(MSI-L),and 22 patients had microsatellite stability(MSS)..Eight patients with appendicular colon adenocarcinoma underwent MSI.One patient had high microsatellite instability(MSI-H)and seven patients had microsatellite stabilization(MSS).The MSI results of 2 cases of posterior signet ring cell carcinoma and 1 case of appendix carcinoid were microsatellite stability(MSS).ConclusionMSI-H,a primary malignant tumor of the appendix,is rare and is difficult to benefit from immunotherapy.The proportion of KRAS mutations in the appendix malignant tumor is higher(9/35),and the BRAF mutation rate is extremely low(0/35).Patients with KRAS and BRAF wild type may benefit from targeted therapy. |
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