Interestingly, Gladkikh et al. [39] showed that cyclin D1 mRNA expression level in reactive lymphoid tissue, although lower than in lymphoma samples, is higher than that of normal B lymphocytes, suggesting a step-by-step induction of cyclin D1, culminating with its functional protein expression in tumors, and likely regulated also by microenvironmental factors. The gene discussed is CCND1; the disease is lymphoma.