Frequency of <em>TP53</em> Mutation in B-Cell Chronic Lymphocytic Leukaemia and its Association with Lymphocyte Doubling Time.

OBJECTIVE: To determine the frequency of TP53 mutation at diagnosis of B-cell Chronic Lymphocytic Leukaemia (B-CLL) in Pakistani patients, and to investigate whether lymphocyte doubling time (LDT) of less than 1 year could be used as a surrogate marker for TP53 mutation.

STUDY DESIGN: A cross-sectional descriptive study. Place and Duration of the Study: Department of Haematology, Liaquat National Hospital, from January 2020 to December 2022.

METHODOLOGY: Patients diagnosed with B-CLL based on the criteria set by International Workshop on Chronic Lymphocytic Leukaemia were included in the study. Clinico-haematological parameters were recorded, and TP53 mutation analysis was performed by fluorescence in situ hybridisation. Patients were followed every 3-6 months after diagnosis with the recent complete blood count (CBC) reports to record CBC parameters and calculate LDT.

RESULTS: A total of 128 B-CLL cases were evaluated, with a mean age of 62 years. Among these cases, 10 patients (7.8%) tested positive for TP53 mutation, while 118 patients (92.2%) tested negative. During the follow-up period, 26 patients were lost to follow-up, with only one patient from the TP53 positive group. In the TP53 positive group, 55.6% (n=5/9) patients had an LDT of less than 1 year, indicating aggressive disease compared to 30.1% (n=28/93) patients in the negative group (p <0.1).

CONCLUSION: TP53 mutations may be associated with shorter LDT, indicating aggressive disease. Further research is needed to fully comprehend the relationship between TP53 mutation and LDT in B-CLL.

KEY WORDS: TP53 mutation, B-Cell chronic lymphocytic leukaemia (B-CLL), Lymphocyte doubling time (LDT).