Relationship Between The Expression Of MDM2 Oncogene And P53 Umor Suppressor Gene And Non-Hodgkin Lymphoma In Childhood

Objective: To investigate the relationship between the expression of MDM2 oncogene and p53 tumor suppressor gene and the malignant grade as well as prognosis of non-Hodgkin lymphoma in childhood, and to provide reference datum for us to evaluate the expression of MDM2 and p53. Methods: It was chosen that 31 cases of NHL as patient group and 8 cases of lymphadenitis as control group. (1) Immunohistochmistry ultrasensitive S-P assay was used to detect the expression of MDM2 protein and p53 protein in pathological tissues in all cases. Positive cells were dyed yellow or brown in nuclei. Positive MDM2 was that the positive cells were ^ 10% tissue cells, which was overexpression of MDM2 protein. Positive p53 was that the positive cells were >5% tissue cells, which meant mutation of p53. (2) Reverse trascription-polymerase chain reaction (RT-PCR) was performed to value the overexpression of MDM2 mRNA in the pathological tissues and single nucleus cells in4peripheral blood. When the ratio of MDM2/P -actin was >16%, it was overexpression of MDM2 mRNA (positive). Result: (1) The rate of overexpression of MDM2 protein and MDM2 mRNA were 64.5% and 613 %, respectively, which had remarkable significant difference as compared to that of control group (p<0.01). The rate of positive p53 protein was 16.1%, which was no difference as compared to that of control group (p>0.05). (2) Analysis of relationship to subgroup among the patients group showed that overexpression of MDM2 protein was not interrelation with classifications of working formulation, cellulor origin, sex, Murphy's stage and involving extranodal sites (p>0.05), and was significant interrelation to classifications of B status, raised serum LDH level and high grade of IPI (p<0.05). Analysis also shown that overexpression of MDM2 mRNA was not interrelation to classifications of working formulation, cellular origin, sex and involving extranodal sites (p>0.05), and was significant interrelation to Murphy's high stage and B status (p<0.05), and was remarkably significant interrelation to raised serum LDH level and high grade of IPI (p<0.01). The results also demonstrated that overexpression of MDM2 protein was remarkably significantrelation to that of MDM2 mRNA (p<0.01), and positive p53 protein was not relation to overexpression of MDM2 protein and MDM2 mRNA (p>0.05). Conclusion: (1) The rate of overexpression of MDM2 oncogene was quite high. (2) Overexpression of MDM2 protein in pathological tissues using immunohistochemistry ultrasensitive S-P assay was similar to that of MDM2 mRNA in pathological tissues or single nucleus cells of peripheral blood using RT-PCR method. Both of the two methods might be used to detect overexpression of MDM2 oncogene in the cases of childhood NHL. (3) Overexpression of MDM2 oncogene was related to poor status and poor prognosis in the patients of childhood NHL. (4) Mutation rate of p53 was low in childhood NHL.