Recent studies have shown that histone variant H3.3, a Protein that works closely with chromatin to package and regulate genetic material within cells, and in particular its clipped form, may play a key role in silencing genes that regulate cancer cell growth. Scientists have found that histone H3.3 and its clipped form, which lacks 21 amino acids of the histone tail and associated modifications, prevents normal cells from dividing. Clipped H3.3 may be a marker of cells that stop proliferating and has implications for cancer, in particular cancers like melanoma that have a senescence phase.