Normal Blood and Bone Marrow Wt1 Expression Level in Extramedullary Relapse in AML Patient

Abstract

AbstractAbstract 4825Wilms' tumor gene 1 (WT1) that encodes a transcription factor has elevated expression in 90% of AML. High level of WT1 gene expression in bone marrow and peripheral blood of patients with AML indicates the presence of leukemia tumor burden. Thus, quantifying assessment of the level of WT1 could predict relapse. It is important to monitor a universal marker in the absence of target molecular genetic abnormalities in the disease onset. There are few data related to extramedullary relapses. Here we describe the patient with extramedullary relapse without concomitant elevation of WT1 expression.The patient is 22 year old male with the first early bone marrow and CNS relapse of AML. Cytogenetics- (45XY, t (3, 5) (q29; q15), −7, der (7), add (11) (p15)). Blast cells immunophenotype was CD45 + CD34 + CD38 + CD117 +. There was high blast count with high expression of WT1 level (Tabl 1). And there was no expression of other molecular genetic prognostic markers. Therapy with high dose of cytarabine with intrathecal administration of cytotoxic drugs was conducted. The complete hematological and cytogenetic remission was achieved after the first induction. Also there was no any blast cell in the CSF, WT1 expression decreased by 1,87 log (WT1 level became normal). Consolidation of remission with three similar courses with high doses of cytarabine was conducted. Extramedullary relapse during bone marrow and CNS remission with unilateral lesion of the lacrimal gland and the periorbital area( 2.8 × 3.4×4.6 cm )was diagnosed in 6 month. Relapse was confirmed by histological and immunochemical study of the left lacrimal gland biopsy, blasts phenotype was similar to the phenotype of bone marrow blasts at AML onset. WT1 level in bone marrow and peripheral blood remained within normal limits: 15.5 WT1/104 ABL copies and 13.4 WT1/104 ABL copies respectively. Therapy with high dose cytarabine and mitoxantrone was used as an induction. After this therapy a local remission was diagnosed according to MRI. Consolidation courses were followed by a course of radiotherapy to the area of the left orbit. Bone marrow remission and low-level expression of WT1 remained to be normal. Thereafter the patient has undergone unrelated allogeneic bone marrow transplantation. Conclusion.We have described isolated AML relapse without elevation of WT1. A possible reason for normal level of expression of WT1 in patients with extramedullary relapse may be a small amount of the extramedullary formation, its location and features of blood supply of the body area.Table 1Blast count in bone marrowWT1/104 ABL copies in bone marrowAt the diagnosis58%3560,6After the induction1%50,8After the first consolidation course1,4%26,7After the second consolidation course0,4%9,6After the third consolidation course0,4%3,04Follow-up2,4%14,3Follow-up1,4%17,7Extramedullary relapse1,4%15,5Day 14 of ≪HDAC≫3,4%29,4After ≪HiDAC≫6%49,2Follow-up before radiotherapy1,6%15Follow-up after radiotherapy32 [Display omitted] Disclosures:No relevant conflicts of interest to declare.