CD79B mutations in primary vitreoretinal lymphoma: Diagnostic and prognostic potential

Objective Primary vitreoretinal lymphoma (PVRL) is a rare type of lymphoma wherein the lesions are limited to the eyes. PVRL is difficult to diagnose because of the challenges related to obtaining sufficient samples for biopsy. Moreover, PVRL has poor outcomes and often leads to the development of central nervous system (CNS) lesions during its course. Two studies recently reported that approximately 70%-80% of patients with vitreoretinal lymphoma have MYD88(L265P), which is frequently mutated in primary CNS lymphoma (PCNSL). PCNSL is closely associated with PVRL. The mutation of CD79B(Y196) has been also frequently detected in PCNSL. Thus, we examined the mutation in PVRL to clarify its diagnostic and prognostic potential. Method By using direct sequencing and allele-specific polymerase chain reaction, we examined the mutation of CD79B(Y196) and MYD88(L265P) in the DNA extracted from the vitreous fluid of 17 patients with PVRL upon diagnosis. We also retrospectively analyzed their prognostic potential for PVRL. Results Among the included patients, six patients (35%) were found with CD79B(Y196) mutations. Twelve (71%) patients were positive for MYD88(L265P), and six samples from patients with benign uveitis were negative for both mutations. Interestingly, six patients with CD79B(Y196) mutations developed CNS diseases significantly earlier (16.5 months) than 11 patients with CD79B(WT) (67 months; P = 0.0135). Conclusion Detecting CD79B(Y196) in vitreous DNA may contribute to the confirmation of the diagnosis and may have a prognostic potential for patients with PVRL.