Statin--a novel marker of nonproliferation. Expression in nonneoplastic lymphoid tissues and follicular lymphomas.

Statin is a 57 kDa nuclear protein exclusively found in noncycling cells. Its expression in hematolymphoid cells had not been examined previously. The authors studied statin immunoreactivity in nonneoplastic lymphoid tissues from 26 lymph nodes, 3 tonsils, and 2 spleens. Statin was detected primarily in small lymphoid cells and histiocytes, along with such accessory elements as fibroblasts and endothelial cells. The distribution of positive cells showed an inverse correlation with the proliferative activity of the various lymphoid compartments. Statin labeling was also quantified in 15 follicular lymphomas and compared with that in hyperplastic follicles. Although reactivity in benign germinal centers was less than that in neoplastic follicles, this difference did not prove statistically significant. Statin provides an alternative to proliferation-associated parameters, such as Ki-67 and proliferating cell nuclear antigen, in the analysis of hematolymphoid processes and may be helpful in the dissection of their kinetic heterogeneity.