Significance Of C-myc Expression In T Lymphoblastic Lymphoma /leukemia And Its Relation With Prognosis

Objective:To study the C-myc gene and protein in T Lymphoblastic lymphoma/ leukemia(T-LBL/ALL) and its relationship to prognosis. Methods:60 cases of T-LBL/ALL paraffin specimens coming from Shanxi Tumor Hospital has a detailed clinical and follow-up data were marked by using immunohistochemical En Vision method for CD1 a, CD3, εCD3, CD7, CD10, CD34, CD43, CD45 RO, CD99, Td T, CD20, CD23, MPO, Ki-67 and C-myc. 20 cases of lymph node reactive hyperplasia were selected as normal control group. For 60 cases of T-LBL/ALL the experimental group and 20 cases of lymph node reactive hyperplasia control group, fluorescence in-situ hybridization(FISH) for C-myc gene(located on chromosome8q24) was performed to detect its breakage and copy number abnormalities. Results:Among the 60 cases of T-LBL/ALL, immunohistochemistry results showed:the percentages of tumor cells expression of CD1 a, CD3, εCD3, CD7, CD10, CD34, CD43, CD45 RO, CD99 and TDT were 38.3%(23/60), 75.0%(45/60), 45.0%(27/60), 95.0%(57/60), 36.7%(22/60), 23.3%(14/60), 60.0%(36/60), 41.7%(25/60), 96.7%(58/60)and 93.3%(56/60). Separately, while CD20,CD23 and MPO were all negative. A figure of Ki-67 expression≤80% was found in 36 cases and >80% was found in 24 cases. In serum LDH≥250 IU/L group, Ki-67>80% group or IPI=3/4 group, εCD3 positive cases were higher than εCD3 negative cases(P<0.05). C-myc protein positive expression rate of 60 cases T-LBL/ALL was 66.7%(40/60), while 20 cases lymph node reactive hyperplasia were all negative expression(0/20). The C-myc protein positive expression rate difference between the two groups was statistically significant(x2=26.67,P<0.05). C-myc protein expression was positively correlated with the mediatinal width and Ki-67 index(P<0.05). Fluorescence in-situ hybridization results showed that among the 60 cases, C-myc gene with breakage of 8q24 was detected in 6 cases(10.0%), and copy number abnormalities in 11 cases(18.3%). 20 cases of reactive lymph nodes were not occurred breakage and copy number abnormalities of C-myc gene. It is not significant between C-myc gene and protein expression(P>0.05). In addition, in 60 cases of T-LBL/ALL, 12(20%) cases of C-myc protein and genetic abnormalities coexist. Log–rank analysis results: The prognosis of C-myc protein positive group was worse than negative group(P<0.05). The relationship of C-myc gene and prognosis was not significant(P>0.05). C-myc protein and genetic abnormality coexist was related with worse prognosis(P<0.05). COX analysis results show that the C-myc protein positive group may be a independent poor prognosis factors(P<0.5). Conclusion:C-myc expression may play an important role on the development of T-LBL/ALL, and was associated with worse prognosis. It may be a independent prognosis factors.