Impact Of Apoptosis, PCNA, P53 And C-myc Expression On Radionsensitivity In Nasopharyngeal Carcinoma

Objective To study the correlation between apoptosis, proliferating cell nuclear antigen(PCNA), P53 Protein and c-myc expression, and the relationship between they and radionsensitivity in nasopharyngeal carcinoma (NPC) . Methods Thirty-one patients histologically Proven to be nasopharyngeal squamous cell carcinoma were eligible to enter into this study. All patients in this study were biopsied from nasopharynx for two times ,first biopsy's samples were performed before irradiation,and second ones were taken after receiving radiation dose of 1520CGy. Apoptosis cells were determined by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL)method. PCNA, P53 proteint and c-myc were determined by immunohistochemical S~P staining technique. Results The apoptosis rate(AR) of radiation-induced was significantly higher than that before radiotherapy(P<0.01). The percentage of PCNA after radiotherapy was obviously lower than that before radiotherapy (P<0.01). Radiosensitivity of tumor cells was positively associated with the PCNA expression beforeradiation, AR of radiation-induced and down values of PCNA after radiation(P<0.01), and was not associated with spontaneous AR, P53 proteint and c-myc(P>0.05). Spontaneous AR has a negative relationship with PCNA, P53 proteint and c-myc(P<0.01). However, the AR of radiation-induced has a positive relationship with percentage of PCNA(P<0.001), and has a negative relationship with P53 proteint and c-myc(P<0.01). The percentage of PCNA has a positive relationship with P53 proteint and c-myc before radiation(P<0.01).Conclusions Apoptosis and PCNA were closely associated with radiosensitivity in NPC. In addition, P53 proteint and c-myc expressions play modulated roles for apoptosis and cell proliferation.