m7FLIPI and targeted sequencing in high-risk follicular lymphoma

Patients with follicular lymphoma (FL) refractory to front-line immunochemotherapy (ICT) have a poor overall survival (OS). Gene mutation analysis may be more accurate than classical risk factors to pick out these patients before treatment. This study aimed to describe the prevalence of selected genetic mutations in a cohort of patients with high-risk FL. Twenty-five patients with FL refractory to front-line ICT and 10 non-refractory patients matched for age, sex, and FLIPI score were included. We sequenced 18 genes (custom targeted sequencing panel) previously reported to potentially have prognostic impact, including the seven genes necessary to determine m7FLIPI risk. The 35 patients had a median age of 62. The FLIPI and FLIPI2 were high in 27 (84%) and 14 (48%), respectively. Three-year progression-free survival (PFS) and OS probabilities were 25% (95% CI, 13%-41%) and 53% (34%-69%), respectively. There were 73 variants in the 18 genes among the 35 patients. The median number of mutations per patient was 1 (interquartile range, 0-3). The most commonly mutated genes were CREBBP (11 of 35, 31%) and EP300 (10 of 35, 29%). EP300 mutations were associated with refractoriness to treatment (10 of 25 among refractory and 0 of 10 among non-refractory). In conclusion, in this study, patients with high-risk follicular lymphoma were genetically heterogeneous.