FOXP1 was known as a tumor promoter with a poor prognosis in follicular lymphoma [15], primary cutaneous large B-cell lymphomas (PCLBCL) [16,17], gastric mucosa-associated lymphoid tissue lymphoma (MALT) [10] and diffuse large B-cell lymphoma (DLBCL) [9,18–20]. Here, FOXP1 is linked to gastric mucosa-associated lymphoid tissue lymphoma.