Clinical And Molecular Delineation Of ALK, ROS1and RET Fusion Genes In Patients With Lung Cancer

Aim:To detect the frequency of ALK,ROS1and RET fusion gene in patients with lung cancer,and analyze the relationship between the frequency and clinical features.We hope this study can Provide reference for clinical individualized treatment of lung cancer.Material and Methods:1.205fresh tumor tissue specimens of lung cancer were screened with fiber bronchoscope from the second Xiangya Hospital of Centre-south University from October2011to April2013.205Chinese patients with lung cancer were enrolled on the basis that they were diagnosed as lung cancer by the Department of pathology of the second Xiangya Hospital and were defined the pathological classification.All fresh tumor tissue specimens were keeping in the-80℃.2. This study examined205lung cancers by Western blotting with the ALK,ROS1and RET fusion gene specificity antibody,after detecting each specimen’s proteins.3. As to positive samples by WB,we test and verify the correspondent Paraffin embedding formalin fixed tissue samples with Immunohistohemitry (IHC).4.The comparison of the ALK-positive and negative patients, the ROS1-positive and negative patients and the RET-positive and negative patients were made in age, gender, smoking history,pathologic type and Pathologic differentiaion degree.5. Statistical analysis were performed by SPSS19.0statistical software. Comparison their clinical features between ALK, ROS1and RET positive and negative patients by Continuity Correctionχ2Test and Fisher’s exact test. All p values were based on a two-sided hypothesis, p <0.05was defined as statistical difference.Results:l.The average age of205lung cancer patients was58.72±9.31yesrs old,and the range is32to80yesrs old.There were98patients younger than average age,accounting for47.8%;107patients older than average age,accounting for52.2%.There were169male, accounting for82.4%;36female,accounting for17.6%.In the smoking history,there were48non-smoker patients, accounting23.4%;157smoker patients, accounting76.6%. In the pathological type,124patients were squamous cell carcinoma, accounting60.7%;31patients were adenocarcinoma, accounting14.9%;3patients were squamous adenocarcinoma, accounting1.5%;42patients were small cell lung cancer,accounting20.4%;3patients were neuroendocrine tumor, accounting1.5%;1patients was mesothelioma of pleura, accounting0.5%;1patients was bronchial mucous epidermoid tumor, accounting0.5%.In the tumor differentiation degree of103assessed cases,44patients were Poor differentiation, accounting42.7%;40patients were moderate differentiation,accounting38.8%;19patients were high differentiation, accounting18.5%.2.6cases(2.9%) among205tumor tissue samples had ALK gene mutation, including5cases were fusion gene,1case was ALK wild type;5cases(2.4%) among205tumor tissue samples had ROS1gene mutation, including4cases were fusion gene,1case was ROS1wild type;2cases(1.0%) among205tumor tissue samples had RET fusion gene mutation。3. Both ALK positive and negative patients had not statistical difference in age (p=0.48), gender (p=0.95), smoking history (p=0.57), pathologic type (p=0.95);Both ROS1positive and negative patients have not statistical difference in age (p=0.21), gender (p=0.89), smoking history (p=0.39), pathologic type (p=0.68); Both RET positive and negative patients have not statistical difference in age (p=0.95), smoking history (p=0.35), pathologic type (p=0.06), while had Statistical significance in gender (p=0.03).4. According to the results of constitute of the clinical features of ALK fusion positive patients, positive patients are more common in smoking(60%,3/5),male(80%,4/5),and also exist in small cell lung cancer. According to the results of constitute of the clinical features of ROS1positive patients, positive patients are more common in male(75%,3/4), Squamous cell carcinomas (75%,3/4). According to the results of constitute of the clinical features of RET positive patients, positive patients are more common in women/non-smoking, and can exist in small cell lung cancer.5.There was no case with two or more gene mutation of ALK, ROS1and RET at the same time.Conclusions:1.ALK, ROS1and RET fusion gene mutation represents a new molecular subtype of lung cancer, the frequency of this three fusion gene are very low in nonselective lung cancer, especially the frequency of ROS1and RET, and it is consistent with the previous reported in the literature.2.ALK fusion gene-positive patients are more common in the unselective lung cancer patients who are smokers, men,and it is noteworthy ALK fusion was also detected in small cell lung cancer; ROS1fusion gene-positive patients are more common in the unselective lung cancer patients who are smokers,men,and squamous carcinoma; RET fusion gene-positive patients are more common in the unselective lung cancer patients who are women/non-smokers,and it is noteworthy RET was also detected in small cell lung cancer.3.The gene mutations of ALK, ROS1and RET are not co-exist simultaneously. This can provide a theoretical basis and important referencement for the standardization of lung cancer genetic screening.4.Western blotting is a effective and feasible technology for fusion gene testing in lung cancer patients.5.The lung cancer tissue samples by fiber bronchoscope is as good as the samples by surgical operation for gene diagnosis for lung cancer patients, especially for the late lung cancer patients.