Prognostic Predictive Value of ITPKB Mutation's Variant Allele Frequency in Diffuse Large B-cell Lymphoma

Objective To investigate the correlation between ITPKB mutation's variant allele frequency (VAF) and prognosis of diffuse large B-cell lymphoma (DLBCL). Methods This study included 155 patients with DLBCL initially diagnosed in the People's Hospital of Xinjiang Uygur Autonomous Region from June 2014 to December 2020. Paraffin-embedded tumor tissue specimens were obtained, and tumor tissue DNA was extracted. A total of 475 hotspot genes including ITPKB were detected by the next generation sequencing to analyze the relationship of the VAF of high-frequency mutant gene with progression-free survival (PFS) and overall survival (OS). Results The mutation frequency of ITPKB was 18.71%. The PFS was significantly shorter in the patients with ITPKB mutations than in those without mutations (37 months vs. 108 months; HR=1.643, 95%CI: 0.920-2.934, P=0.093). The R-language based web tool was used to find the best VAF cutoff to differentiate prognosis. The patients were divided into two groups (VAF High vs. VAF Low+Wt) according to their VAF values. The optimal VAF threshold for ITPKB was 27.48% (HR=3.480, 95%CI: 1.70-7.13, P=0.00027). Multivariate Cox analysis was conducted using clinical indicators such as age, gender, COO classification, IPI, and LDH, and the results showed that PFS was associated with high ITPKB VAF (≥28%) (HR=3.592, 95%CI: 1.738-7.425, P < 0.001) which was an independent adverse predictor of PFS. Conclusion The high load of ITPKB mutation is an independent risk factor for the PFS of patients with DLBCL, and the VAF of ITPKB mutation has a prognostic predictive value for patients with DLBCL.