ATM and mantle cell lymphoma: The most prevalent second hit in MCL includes ataxia-telangiectasia mutated (ATM) aberrations, accounting for approximately 50% of patients with newly diagnosed MCL (Malarikova et al. 2020; Camacho et al. 2002; Mareckova et al. 2019; Karolová et al. 2023; Greiner et al. 2006; Ahmed et al. 2016).