Expression of retinoblastoma protein in child acute leukemia cells and its clinical significance

The research was aimed to detect the expression levels of retinoblastoma protein (pRb) in child acute leukemia cells, and to explore its possible association with leukemia cells cycle, the risk of disease, minimal residual disease (MRD) monitoring and prognosis of B-ALL. Flow cytometry (FCM) was used to detect the expression of pRb in 89 cases of acute leukemia (including 25 AML, 10 T-ALL and 54 B-ALL) and bone marrows from 7 normal children (control group). Meanwhile the cell cycle in some cases was analyzed. The results showed that (1) the FCM could accurately detect the expression of pRb in acute leukemia cells; (2) the high level of pRb expression was frequent in all types of child acute leukemias. In the same case, the expression of pRb was significantly increased in leukemia cells when compared with non-leukemia cells. And no detectable pRb protein was found in partial cases of acute leukemia; (3) there was a close relation between expression of pRb and the cell cycle of leukemia cells, the number of G(1) phase cells in pRb positive case of B-ALL was more than that in pRb negative case (92% vs 77%); (4) in B-ALL, the level of pRb expression in MRD positive group was significantly lower than that in MRD negative group (P < 0.05), but pRb expression was stable in non-leukemia cells during therapy; (5) pRb expression was related to the early response to therapy in B-ALL, the expression of pRb was significantly increased in sensitive group when compared with insensitive group (P < 0.05). It is concluded that high level or absence of pRb expression can be found in child acute leukemia cells. The expression of pRb is positively related to cell cycle of leukemia cells, MRD monitoring and the early response to therapy. In short, the detection of pRb expression level can guide the therapy and the evaluation of prognosis in B-ALL.