Second‐To‐Fourth Digit Ratio (2D:4D) in Breast Cancer: A Systematic Review
Abdullah Avcı, Emine Kaplan Serin · 2026
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Description
Avcı and Kaplan Serin review whether the ratio of index finger length to ring finger length relates to breast cancer risk. That ratio, called 2D:4D, is set before birth and is read as an indirect sign of hormone exposure in the womb. Their 2026 systematic review searched three databases under standard reporting rules and kept observational studies that compared women with breast cancer to healthy controls.
Seven studies covering 13,556 women met the criteria. Most case control studies found higher finger ratios in women with breast cancer on one or both hands. But the one study that followed women forward in time found a link for the left hand only, and the largest multi center study found no steady link at all. The authors call the overall signal possible but uneven, and they ask for larger forward looking studies before the ratio earns any role in risk checks.
Catalog record
| CREATOR | Abdullah Avcı, Emine Kaplan Serin |
|---|---|
| YEAR | 2026 |
| COLLECTION | PAPERS |
| FORMAT | TXT |
| FILE SIZE | 29 KB |
| LICENSE | https://creativecommons.org/licenses/by/4.0 |
| RIGHTS | CC BY |
| SOURCE | Europe PMC |