[The influence of additive clonal chromosome abnormalities in Ph negative cells on the efficacy of chronic myeloid leukemia]

Objective: To investigate the influence of additional clonal chromosome abnormalities in Ph negative cells (CCA/Ph(-)) on the efficacy of chronic myeloid leukemia (CML) after tyrosine kinase inhibitors (TKI) treatment. Methods: The clinical data of 28 CML patients with CCA/Ph(-) treated in Henan Cancer Hospital from July 2014 to December 2017 were analyzed retrospectively. The univariate analysis was carried out by Kaplan-Meier method. Multivariate analysis was done by Cox proportional risk model. Results: A total of 28 CCA/Ph(-)patients were recruited including 17 males and 11 females with median age of 42.5 years old. The most common CCA/Ph(-)were trisomy 8 (60.7%), monosomy 7 (14.3%). 64.3% CCA/Ph(-)were transient and 35.7% recurrent (more than 2 times). Cytopenia in two or three lineages of peripheral blood was seen in 42.9% patients. As to the efficacy, 89.3% patients achieved major cytogenetic response (MCyR), 25% with major molecular response (MMR). The median follow-up time was 26.5 months. Treatment failure (TF) of TKI occurred in 32.1% patients with median duration of response 8 (1-41) months. Univariate analysis showed that TF rate was significantly correlated with the frequency of CCA/Ph(-)and cytopenia (all P<0.05). The MMR rate was also significantly correlated with cytopenia (P<0.05). Cytopenia of two lineages or pancytopenia was an independent risk factor related to MMR rate (RR=3.868, 95%CI 1.216-12.298, P=0.022) . Conclusions: Cytopenia in CCA/Ph(-)appears to be an independent risk factor of MMR in CML patients with TKI treatment. The recurrent CCA/Ph(-)may link to higher treatment failure rate. Drug withdrawal or alternative strategy should be considered according to response and the ABL kinase mutations.

Clinical implications of clonal chromosomal abnormalities in Philadelphia negative cells in CML patients after treated with tyrosine kinase inhibitors

Emergence of clonal chromosomal abnormalities in Philadelphia chromosome-negative (CCA/Ph-) cells in chronic myeloid leukemia (CML) patients during the treatment with tyrosine kinase inhibitors (TKIs) is an interesting phenomenon. Although previous studies revealed some potential impact of CCA/Ph- on CML patients' outcome, clinical significance of CCA/Ph- in CML patients remains to be further elucidated. We retrospectively reviewed the patients with CML evaluated at Genoptix Medical Laboratory in Carlsbad, California from 2005 to 2015. Twenty-four CML patients with CCA/Ph- cells were identified. These include 18 patients with single chromosomal abnormality, 4 patients with double chromosomal abnormalities, and two patients with complex cytogenetic abnormalities. In addition to trisomy 8 and monosomy 7, we identified that 20q- was also a common abnormality in CCA/Ph- cells. Most of the patients with CCA/Ph- cells demonstrated no significant dysplasia or increased blasts with two exceptions: one patient with persistent 7q- exhibiting mild dysmegakaryopoiesis, suggestive of an early evolving myelodysplastic syndrome, and another patient with complex cytogenetic abnormalities who developed acute myeloid leukemia after gained MLL amplification. One patient with complex cytogenetic abnormalities showed optimal response to TKI treatment, no overt dysplasia, and no disease progression during almost 4-years of follow-up. More interestingly, FISH tests could identify more cases with double chromosomal abnormalities and these cases showed suboptimal responses to TKI treatments. Our observation indicates that 20q- was also a common abnormality in CCA/Ph- cells, further FISH tests revealed additional CCA/Ph-, and the majority of CML patients with two or more chromosomal abnormalities in Ph- cells showed inferior response to TKI treatments. The results of our study suggest that CML cases with CCA/Ph- may represent a group of patients with heterogeneous genetic alterations.