The impact of cyclin D1 overexpression on the prognosis of ER-positive breast cancers: a meta-analysis.

Cyclin D1 (CCND1), a key regulator of cell cycle progression, is overexpressed in many human cancers, including breast cancer. However, the impact of CCND1 overexpression in these cancers remains unclear and controversial. We conducted a systematic literature search in PubMed and EMBASE with the search terms "cyclin D1", "CCND1", "breast cancer", "prognosis", and potential studies for analysis were selected.