A New Clock is Running for Multiple Myeloma: Circadian Clock Protein-Period 3 (PER-3) Polymorphism

Circadian Clock Protein PERIOD 3 (PER-3) is situated on chromosome 1p36.23 and has a polymorphic domain that expresses 4 or 5 copies of the 54-bp tandem repeat sequence. PER-3 gene polymorphisms play a role in the dysregulation of the immune system. This study intended to investigate the distributions and clinical effectiveness of the PER-3 gene polymorphism in multiple myeloma (MM) patients. One hundred fifty patients diagnosed between January 2007-2009 and 100 healthy individuals were included in this study. All patients were suitable for autologous stem cell transplantation (ASCT) at first evaluation, and after 4 courses of VCD at least partial remission, ASCT was carried out. Later, LD was used as maintenance. Genotypes of PER-3 gene of patients and healthy controls were statistically compared before treatment. In addition, these genotypes’ effects on overall and progression free survival (OS and PFS) were investigated. Median PFS in the 5R/5R genotype was found to be significantly longer, albeit low, at 86% (p = 0.046). In the statistical analysis performed between the 4R/4R genotype and others, the PFS of patients with 4R/4R was found to be significantly shorter at 40.4 months (p = 0.026). Patients with the 4R/4R genotype would have a risk of 2.049 times of a shorter PFS (p=0.009). With this first study investigating the effect of a circadian gene in MM, the net effect of PER-3 gene polymorphism on PFS was revealed, and it will be a guide for future studies.