Efficacy of Chemotherapy in Acute Leukemia Patients Resistant to Previous Standard Treatment According to the Series Measurement of WT1 Gene Expression

• Main Authors: NN Mamaev, YaV Gudozhnikova, TL Gindina, IM Barkhatov, AI Shakirova, VA Katerina, MV Gubina, ES Nikolaeva, EV Semenova, OV Paina, EI Darskaya, OV Pirogova, VV Porunova, IS Moiseev, IA Mikhailova, BI Ayubova, VM Kravtsova, SN Bondarenko, LS Zubarovskaya, BV Afanas’ev
• Format: Article
• Language: Russian
• Published: Practical Medicine Publishing House 2018-01-01
• Series: Kliničeskaâ onkogematologiâ
• Subjects: acute leukemia; induction chemotherapy; molecular monitoring; WT1
• Online Access: http://bloodjournal.ru/wp-content/uploads/2018/01/9.pdf
• ISSN: 1997-6933; 2500-2139

Aim. To estimate the efficacy of chemotherapy in acute leukemia patients resistant to previous standard treatment according to the series measurement of WT1 expression. Materials & Methods. The series measurement of WT1 expression formed the basis of the efficacy estimation of induction chemotherapy in 31 patients (15 men and 16 women aged from 3 months to 68 years; the median age was 28 years) with prognostically unfavourable variants of acute myeloid (AML) and lymphoblastic leukemia (ALL) (23 AML and 8 ALL patients). The WT1 gene expression was measured at baseline and 2–3 weeks after the treatment by the quantitative real-time PCR. The threshold level for detection was 250 copies of WT1/104 copies of ABL. The cytogenetic profile of leukemia cells was assessed by standard cytogenetics and FISH. Results. The baseline expression level of WT1 varied from 305 to 58,569 copies/104 copies of ABL. The expected reduction of WT1 expression after the first induction chemotherapy treatment was reported in 22/23 (96 %) AML patients and in 6/8 (75 %) ALL patients. According to our results WT1 expression reached the threshold in 13/31 (42 %) patients, including 9 AML patients and 4 ALL patients. After 11/31 (35 %) patients received the second course of treatment, WT1 expression level became normal in 8 cases (5 ALL and 3 AML patients). Despite high dose chemotherapy, HSCT and such agents as blinatumomab and gemtuzumab, an unfavourable outcome was observed in 18/31 (58 %) patients including 6 patients with complex karyotype (CK+) and 2 patients with monosomal karyotype (MK+). Once the MK+ and CK+ combination was observed, in another case the MK+ was combined with the prognostically unfavourable inv(3)(q21q26) inversion. Conclusion. Our results show that the molecular monitoring should be included as part of treatment of the prognostically unfavourable acute leukemia. The WT1 gene was shown to be the most appropriate marker. WT1 expression was shown to correlate with the common fusion genes allowing to estimate the blast cell count at the molecular level.