Clinical Significance And Expression Of STAT5a And STAT5b In Human Non-Small Cell Lung Cancer

Abstract:Objective:To investigate the expression of STAT5a (Signal transducer and activator of transcripton 5a) and STAT5b (Signal transducer and activator of transcripton 5b) in NSCLC (Non-Small Cell Lung Cancer) and normal lung tissue, and to explore their possible roles in the tumorigenesis of NSCLC or tumor invasion and metastasis.Method:40 cases of NSCLC specimenes and 20 cases of normal lung tissues were subjected to immunohistochemical staining (SP) for STAT5a, STAT5b.The NSCLC tissues were obtained from 40 patients undergoing lung cancer resection at the Department of Surgery, the Affiliated Hospital of Luzhou Medical College. No patient had received chemotherapy or radiation therapy before surgery. Detailed clinicopathological parameters including age, gender, tumor diameter, stage, lymph,node metastasis, and degree of differentiation are as following.There were 29males and 11 females.Their ages ranged from 35 to 78.whose age<60 were 22 and≥60 were 18.There were 26 squamous carcinomas and.14 adenocarcinomas.The specimenes whose tumor diameter>3cm were 26 compared 14 specimenes whose tumor diameter≤3 cm. The metastatic lymph node specimens were 18,while 22 specimens had no nodal metastasis performance. NSCLC tissues that belongde toⅠ-Ⅱstage were 24 and that belonged toⅢ-Ⅳstage were 16.Moderately differentiated and well-differentiated tumors were 30, poorly differentiated tumors were 10.All the specimens were dealt with formalin fixation, paraffin imbedding and section-cutting. After deparaffinage and hydration, we rinsed the sections with distilled water and soaked them in phosphate buffer saline. Then they were subjected to an antigen retrieval procedure by heating.Endogenous peroxidase activity was blocked using 3% H2O2 solution and nonspecific binding sites were blocked by incubating with goat serum. The slides were incubated with appropriate primary antibody (Rabbit anti-STAT5a Polyclonal Antibody, Rabbit anti-STAT5b Polyclonal Antibody).Wait 2 hours and then wash them with PBS.The second antibody with biotin labeling were dropped to the slides and incubated. Wait 15 minutes and then wash them with PBS.After that, the slides were incubated with S-A/HRP for 15 minutes and then washed with PBS. Immunologic reaction was developed using DAB.The slides were counterstained with hematoxylin, mounted and then observed through microscope. Consider the cells whose cytoplasm or nucleus had brownish yellow matter as positive cells.STAT5a and STAT5b positive signal was localized in both cytoplasm and nucleus, but predominantly in cytoplasm. They were divided into 4 levels according to proportion of positive cells and colour depth of each slice. Results:(1)Protein levels of STAT5a and STAT5b were significantly increased in NSCLC tissue compared with normal tissue (P<0.01). (2) Overexpression of STAT5a wasn't associated with age of onset, tumor diameter, nodal metastasis, tumor differentiation and stages in NSCLC (P> 0.05).STAT5b overexpression was association with gender of patients in NSCLC (P<0.05),but STAT5a overexpression wasn't association with gender of patients in NSCLC(P>0.05).The expression of female patients than male patients(P<0.05).(3) There was not a significant correlation between the expressions of STAT5a and STAT5b in NSCLC (P>0.05).The overexpression of STAT5a closely than STAT5b in NSCLC.Conclusion:(1)The levels of STAT5a, STAT5b proteins were higher in NSCLC than in normal lung tissue. The overexpression of STAT5a, STAT5b might play important roles in the tumorigenesis of NSCLC.(2) There was no association between STAT5a, STAT5b overexpression and the age of onset, tumor diameter, lymph node metastasis, tumor differentiation and stages in NSCLC.It indicates that those two proteins have no effct on tumor progression, invasion and metatasis, STAT5b overexpression was association with gender of patients in NSCLC, but STAT5a overexpression wasn't association with gender of patients in NSCLC.The expression of female patients than male patients.(3) There was also no correlation between the expressions of STAT5a and STAT5b protein. So they might have no synergistic action with eath other in NSCLC.They might play independent roles in oncogenesis of NSCLC,The overexpression of STAT5a closely than STAT5b in NSCLC.