Transcriptional expression of p63 gene in small-cell lung carcinoma and lung adenocarcinoma / 中国组织工程研究

ABSTRACT

BACKGROUND: The role of p53 gene in human lung cancer has been confirmed. Since the discovery of p63 gene as the homologue of p53, its role and possible mechanism-have aroused the attention of investigators all over the world. But the principle concerning transcription and expression of p63 in small-cell lung carcinoma (SCLC) remains unclear.OBJECTIVE: To investigate the level of the expression of p63 gene in SCLC and lung adenocarcinoma tumor tissues, peri-carcinoma tissues and normal tissues, and observe the expression of p63 protein in these tissues so as to understand the principle and clinical significance concerning p63gene expression in SCLC and lung adenocarcinoma.DESIGN: Controlled experiment.SETTING: Department of Thoracic and Cardiovascular Surgery, Research Institute of Field Surgery of Daping Hospital of Third Military Medical University of Chinese PLA.PARTICIPANTS: Six SCLC specimens dissected during the surgical operation in Daping Hospital, Third Military Medical Univers ity of Chinese PLA, between October 2000 and September 2002 , were recruited. There were 4 male and 2 female patients aged 42 to 67 years (mean age of 50.7years); 15 specimens of lung adenocarcinoma were also collected at the same time. Tumor tissues, peri-carcinoma tissues and normal tissues were chosen in each specimen.METHODS: Reverse transcriptase polymerase chain reaction (RT-PCR)was used to detect and compare the transcription expression of two subtypes of p63 gene (TAP63 and △NP63)in the tumor tissues of 6 cases of SCLC and 15 cases of lung adenocarcinoma. At the same time, immunohistochemical staining technique was used to detect the expression of p63protein in the above tissues.MAIN OUTCOME MEASURES: ① Expression of p63 protein detected by RT-PCR in tissue specimens. ② Expression of p63 protein detected in tissue specimens detected by immunohistochemical staining technique.RESULTS: ① Expression of p63 protein detected by RT-PCR in tissue specimens The positive expression of △Np63 gene could be found in 5cases (83%, 5/6) of SCLC cancer tissues and 1 case of SCLC peri-carcinoma tissues (17%, 1/6), and the expression of TAp63 was not observed in all of the tumor, peri-carcinoma and normal tissues of SCLC. There was no expression of △Np63 or TAp63 in tumor, peri-carcinoma and normal tissues of lung adenocarcinoma. ② Expression of p63 protein detected by immunohistochemical staining in tissue specimens The positive expression rate of p63 protein in SCLC tumor tissues was significantly higher than that in lung adenocarcinoma tissues [83% (5/6), 17% (1/6), P ＜ 0.01].CONCLUSION: p63 gene shows positive expression in SCLC, among which the expression level of △NP63 is increased while the expression level of p63 protein is obviously higher in SCLC than in adenocarcinoma tissues, which may be related to its regulatory role in the occurrence and development of SCLC. It is presumed that△NP63 gene has high transcription expression level in SCLC, which might inhibit cellular apoptosis, promote the proliferation of tumors, play the role as an oncogene. It suggests that p63 may be one of the factors influencing the prognosis of SCLC.