Clinical Prognostic Analysis And Whole Exome Sequencing Of Patients With Adenosquamous Carcinoma Of The Lung After Surgical Resection

OBJECTIVE:According to the World Health Organization’s classification,adenosquamous carcinoma(ASC)is defined as a carcinoma showing components of both adenocarcinoma(AC)and squamous cell carcinoma(SCC),with each component comprising at least 10%of the tumor.Previous studies showed that the incidence of this rare tumor was between 0.4%and 4%of all lung cancers.Few studies have reported on series of ASCs,but all have emphasized the aggressive behavior of these tumors and a worse outcomethan AC or SCC.The clinical records of patients who underwent surgical treatment for lung cancer in the two medical center from January 2010 to December 2015 were reviewed.Of these,a total of 58 patients with pathologically diagnosed ASCs.This study aimed to not only analyze the clinical characteristics,biological behavior and prognosis of the patients with ASCs,but also use next-generation sequencing technology to perform whole exome sequencing on patients of ASC.METHODS:A total of 58 patients with pathologically diagnosed ASCs underwent surgical treatment for lung cancer in the two institutes from January 2010 to December 2015(First affiliated hospital of Guangzhou Medical University and First People’s Hospital of Foshan City).The preoperative evaluation included chest roentgenography,bronchoscopy,computed tomography of the chest,pulmonary function texts(PFTs),brain CT orMR,abdominal CT or ultrasound,bone scan or positron emission tomography to exclude brain,liver,adrenal or bony metastasis.EBUS-TBNA was not performed in all patients but was routinely performed according to the result of preoperative evaluation,including tumor size,nodal extension,planned resection,and need for induction therapy.N3 disease and distant metastases precluded surgical treatment.Tumor stages were classified based on the tumor,node and metastasis(TNM)staging system according to the 8th edition of the TNM classification for lung cancer.The aim of this study was to collect all the clinical data and follow-up information,and then analyze and summarize the clinical characteristics(age,gender,relation with smoking,signs and symptoms et al.),medical imaging features(CT scans and PET/CT scans),histological features(histology,immunohistochemistry),and prognosis(3 years and 5 years survival).Follow-up information of all patients was obtained through clinical follow-up center.And whole exome sequencing on patients of ASC was performed by next-generation sequencing technology.RESULTS:1.All the basic information of 58 ACS patients were collected and summarized.The incidence of ASC was 1.6%and all the patients underwent complete resection(33 males,25 females;average age 62.4±9.2 years old).The cumulative postoperative 3-and 5-year survival rates were 56%and 48.2%,respectively.No difference of overall survival(OS)was found in patients with or without visceral pleural invasion(VPI),nor vascular invasion(Ⅵ).2.Patients with ASC containing acinar predominant adenocarcinoma had better survival than those with non-acinar predominant ASC(p=0.03).Multivariate analysis showed gender,pathological subtype,and TNM staging to be independent prognostic factors.3.EGFR mutations of ASC is significantly correlated with the size of the tumors.The larger the tumors,the higher the positive rate of the mutation.4.Mutations of EGFR,KRAS and ALK genes are mutually exclusive in adenosquamous carcinoma of the lung.Most adenosquamous lung cancers have known driving mutations and may benefit from targeted therapy.5.We sequenced the genomes of 5 Chinese patients with adenosquamous carcinoma of the lung and their normal tissues,and analyzed the genes with significant high frequency mutations.We found that CADM1 may be the driving gene of adenosquamous carcinoma of the lung,and MUC6 may be a potential gene related to adenosquamous carcinoma of the lung.6.After interfering with the expression of MUC6 gene,the proliferation,invasiveness and tumorigenicity of lung adenosquamous carcinoma cell lines were inhibited.CONCLUSION:ASC is a uncommon and aggressive subtype of non-small cell lung cancer.ASC tends to involve elder male patients.The surgical treatment including pulmonary segmentectomy must be combined with chemotherapy and radiotherapy.Multivariate analysis showed gender,pathological subtype,and TNM staging to be independent prognostic factors.Further prospective studies are warranted to clarify this rare tumor.Most of lung adenosquamous carcinomas have known driving mutations.The EGFR mutation of lung adenosquamous carcinomas is significantly related to the size of tumors.CADM1 may be the driving gene of lung adenosquamous carcinomas,and MUC6 may be the potential related gene of lung adenosquamous carcinomas.