In acute promyelocytic leukaemia (APL), the RAR alpha (RARA) gene on chromosome 17, finds itself involved in chromosomal recombination with one of several different potential partner genes (designated “X”), i.e. PML, PLZF, NuMA, NPM1, FIP1L1, PRKAR1A, STAT5b or BCOR, generating X/RARA fusion proteins [3], [4]. Here, PML is linked to acute promyelocytic leukemia.