OBJECTIVETo explore the relationship between long (L) type PML-RAR alpha fusion gene and the prognosis of patients with acute promyelocytic leukemia (APL).

METHODSPML-RAR alpha fusion gene was detected by RT-PCR in 33 APL patients. The optical density of three bands including E5 (+) E6 (+) 636 bp (no deletion), E5 (-) E6 (+) 492 bp (exon 5 deleted) and E5 (-) E6 (-) 232 bp (both exon 5 and exon 6 deleted) was measured by a UVP analysis system and their relative proportions were calculated. The relative expression level of each splicing band, initial WBC count and age were statistically (for single and multi-factor analysis) analyzed with prognosis.

RESULTSThe relative expressions of E5 (-) E6 (+) and E5 (-) E6 (-) in death group were obviously different from that in first complete remission (CR1) group (P < 0.01), but do not for E5 (+) E6 (+) (P > 0.05). The relative expression levels of E5 (-) E6 (+), E5 (-) E6 (-) and E5 (+) E6 (+) were 0.23 +/- 0.12, 0.58 +/- 0.18, 0.20 +/- 0.09 in death group, and 0.45 +/- 0.16, 0.23 +/- 0.12, 0.31 +/- 0.16 in CR1 group, respectively. Initial WBC count and age was no difference between the two groups (P > 0.05). Logistic regression analysis showed that the expression of E5 (-) E6 (+) had no effect on the prognosis (B = 3.475, P = 0.492), but the expression of E5 (-) E6 (-) showed a negative correlation with prognosis (B = -19.660, P = 0.046).

CONCLUSIONSThe high expression of E5 (-) E6 (-) is correlated with the poor prognosis for patients with APL.