ABSTRACT Chronic lymphocytic leukemia is the most common hematologic malignancy among adults in Western countries. Several studies show that somatic mutations in the TP53 gene are present in up to 50% of patients with relapsed or refractory chronic lymphocytic leukemia. This study aims to review and compare the methods used to detect somatic TP53 mutations and/or 17p deletions and analyze their importance in the chronic lymphocytic leukemia diagnosis and follow-up. In chronic lymphocytic leukemia patients with refractory or recurrent disease, the probability of clonal expansion of cells with the TP53 mutation and/or 17p deletion is very high. The studies assessed showed several methodologies able to detect these changes. For the 17p deletion, the chromosome G-banding (karyotype) and interphase fluorescence in situ hybridization are the most sensitive. For somatic mutations involving the TP53 gene, moderate or high-coverage read next-generation sequencing and Sanger sequencing are the most recommended ones. The TP53 gene mutations represent a strong adverse prognostic factor for patient survival and treatment resistance in chronic lymphocytic leukemia. Patients carrying low-proportion TP53 mutation (less than 20-25% of all alleles) remain a challenge to these tests. Thus, for any of the methods employed, it is essential that the laboratory conduct its analytical validation, documenting its accuracy, precision and sensitivity/limit of detection.

ABSTRACT Introduction: The myelodysplastic syndromes (MDS) are a group of heterogeneous clonal hematopoietic stem cell disorders that results in peripheral blood (PB) cytopenias and bone marrow (BM) dysplasia. Dysplasia is the hallmark of the disorder, and must exceed the threshold of 10%. Conventional karyotype (KT) has a role in the classification and prognostication of subtypes. In daily practice, many cases are diagnosed in face of exuberant clinical complains, but cases with dismal evidences pose real difficulties to definitively conclude the case. Material and methods: The objective of this study is to detect cases in which no morphology evidence of dysplasia or increased blasts were observed but KT was decisive for MDS diagnosis. 666 cases were admitted to rule out MDS. Results: There were found 5 (0.75%) cases who presented no evident dysplasia morphology or whose dysplasia was borderline but the karyotype was decisive because showed clonal evidence. The karyotype was: case 1: 46,XY,del(5q)(q13q33),del(11)(q13q23)[7]/46,XY[13]; case 2: 46,XX,del(11)(q21q23)[20]; case 3: 46,XX,del(7)(q22q34)[4]/46,XX[8]; case 4: 47,XX,del(5)(q13q33),+mar[12]/46,XX[8] and case 5: 46,XXt(2;11)(p21;q24),del(4)(?q25),del(21)(q22)[14]/46,XX[6]. Conclusion: Patients with cytopenia and insufficient or borderline evidence of dysplasia may experience a long journey before a MDS diagnosis is made. Cytogenetics studies may abbreviate this pathway when clonal aberrations considered presumptive of MDS are detected. This study shows that karyotype should still be considered as a diagnostic tool.

ABSTRACT Chronic lymphocytic leukemia is characterized by clonal proliferation and progressive accumulation of B-cell lymphocytes that typically express CD19+, CD5+ and CD23+. The lymphocytes usually infiltrate the bone marrow, peripheral blood, lymph nodes, and spleen. The diagnosis is established by immunophenotyping circulating B-lymphocytes, and prognosis is defined by two staging systems (Rai and Binet) established by physical examination and blood counts, as well as by several biological and genetic markers. In this update, we present the recommendations from the Brazilian Group of Chronic Lymphocytic Leukemia for the diagnosis and treatment of chronic lymphocytic leukemia. The following recommendations are based on an extensive literature review with the aim of contributing to more uniform patient care in Brazil and possibly in other countries with a similar social-economic profile.