TP53 and mantle cell lymphoma: Based on the most recent National Comprehensive Cancer Network (NCCN) guidelines (v.5.2021), besides relevant cell marker assessment by flow cytometry/IHC and cytogenetics karyotype/FISH studies for confirming a diagnosis of MCL, the only molecular testing considered essential is TP53 gene sequencing, for patients with expected aggressive clinical course (69) (see Frontline Treatment for MCL section under Current Treatment Options below).