OncoGene ® MAGAZINE Home of Biomarkers in Oncology

Chronic Lymphocytic

Molecular Markers

in Chronic lymphocytic Leukemia

Expert Opinion

Quick Facts

Genetic lesions as prognostic markers
The mutational status of the IGHV genes remains stable throughout the course of the disease and is one of the most important prognostic biomarkers in CLL. In comparison with patients with IGHV- M CLL (~60% at diagnosis), those with IGHV- UM CLL are characterized by the presence of high- risk genetic lesions, an increased propensity to undergo clonal evolution and an association with a shorter TTFT and unfavourable OS


Influence on treatment strategies
During the past 5 years, the dissection of the genetic lesions underpinning CLL, along with the advent of novel drugs, has shifted the treatment strategy in patients with CLL from universal chemoimmunotherapy to a more individualized approach.


At diagnosis, assessment of IGHV mutational status, molecular cytogenetics (using FISH) and mutational analysis of the TP53 gene are currently recommended in the iwCLL guidelines to ascertain the prognostic risk in a given patient


In a patient requiring treatment, these molecular tests are mandatory because they help in identifying the best therapeutic strategy .In patients included in clinical trials, the additional analysis of biomarkers directly informing the response to targeted therapy is advisable.
Finally, complex karyotype analysis, although potentially useful in predicting response, is still considered investigational.


Chronic lymphocytic leukaemia NCCN Practice Guidlines In Oncology

Version4. 2020

iwCLL guidelines for diagnosis, indications fortreatment, response ass...

consensus guidelines of the International Workshop on Chronic Lymphocy...


Prognostic factors in CLL and their relation to outcome ?

The diagnosis of CLL generally requires detection of >5,000 CLL-type cells per microliter of peripheral blood. CLL cells typically express CD19, weak CD20, and CD23 (B-cell antigens), along with CD5 (a T-cell antigen); these are usually assessed by flow cytometry immunophenotyping.

Cytogenetic, molecular, and flow cytometric testing play an important role in prognostication for CLL patients.


Genetics of chronic lymphocytic leukaemia progression?



The overall genomic mutation load seems to be similar in monoclonal B lymphocytosis (MBL) and early stage chronic lymphocytic leukaemia (CLL), as determined in both whole-exome sequencing and whole- genome sequencing studies. When CLL evolves from early stages to overt disease, discrete acquisition of genetic lesions occurs, suggesting that B cell receptor (BCR) signalling and/or
the microenvironment contribute to disease progression41. After the constraints exerted by treatment with chemoimmunotherapy (CIT) or the BCR signalling inhibitor ibrutinib, CLL cells with genetic lesions conferring drug resistance become clonally selected (orange cells).


Finally , CLL can transform from advanced- stage disease to an aggressive lymphoma termed Richter syndrome (RS), although the concurrent diagnosis of CLL and RS is rare In most cases, the RS cells (red cells) derive from the original CLL clone (blue cells) by developing additional genetic lesions.

NOTCH1 mutations, MYC activation and TP53, CDKN2A and CDKN2B disruptions are characteristic genetic lesions of RS65. Patients with CLL receiving ibrutinib can progress in two different ways.

First, in approximately 5% of patients, the disease can evolve in <2 years on treatment to a RS that is clonally related to the underlying CLL.


The time and clinical presentation suggest that ibrutinib selects for a pre- existing RS clone.
Second, 15% of patients, who typically show progression after >2 years of treatment, can develop mutations associated with resistance to ibrutinib (that is, BTKC481S, PLCG2 or ITPKB mutations).

These mutations can be detected using highly sensitive techniques even before the start of ibrutinib treatment (orange cells) and up to 15 months preceding clinical progression, which is characterized by an increase in the size of the lymph nodes and a rise in lymphocyte count and serum lactate dehydrogenase (LDH) levels.




  • Flow cytometry and fluorescence in situ hybridization (FISH) used for follow-up to detect minimal residual disease (MRD)
    • Cytogenomic microarray not recommended for MRD
  • Infectious disease screening prior to and during therapy
    • Hepatitis B – identify infection prior to initiating CD20 monoclonal antibody therapy
      • Monitor all patients with positive test result who are receiving therapy
    • Cytomegalovirus (CMV) antibodies – high risk of CMV reactivation with tyrosine kinase inhibitor (TKI) therapy
      • Monitor every 2-3 weeks in patients using alemtuzumab
    • Herpes simplex virus (HSV) and Pneumocystis jirovecii risk of reactivation of these infections in patients with HIV who undergo therapy
      • HSV and P. jirovecii testing as indicated