These results suggested that ATO-based therapy may ameliorate the unfavorable influence of previously known high-risk features; moreover, CD56 expression remains to be a potentially unfavorable prognostic factor in APL patients.
S-form APL (n = 45) had a higher percent of cells expressing CD2 or CD34 (P < 0.0001 for both) or the neural cell adhesion molecule CD56 (P = 0.001) than L-form APL (n = 66).
A NUP98 gene translocation occurring with a del(6p23) and an add(11)(p15) was determined in a 61-year-old patient with therapy-related atypical chronic myelocytic leukemia after complete remission from acute promyelocytic leukemia that eventually underwent clonal evolution and transformed to CD56-positive acute myelocytic leukemia (French-American-British classification M0).
This case demonstrated clonal evolution from a CD56(-) to a CD56(+) blast population and provided further support for the suggestion that CD56 expression might be an unfavorable prognostic factor in t(15;17) APL.