Long index finger could indicate reduced prostate cancer risk
MedWire News: Men whose index fingers are longer than their ring finger are less likely to develop prostate cancer compared with men who have shorter index, than ring fingers, says a UK research team.
The ratio of 2nd to 4th digit (2D:4D) length - fixed in utero - has previously been shown to be negatively related to testosterone phenotypes, such as sperm counts, and positively related to estrogen concentrations, explain the researchers.
"Accordingly, digit length pattern may act as a proxy indicator for the underlying prenatal testosterone levels," say Kenneth Muir (Warwick University, Coventry) and colleagues.
"We therefore investigated this… to explore whether there is any association between hand pattern and prostate cancer risk," they add.
Using data spanning 1994-2009, the team identified 1524 non-screen-detected prostate cancer patients and 3044 men without the disease, and sent each man a postal questionnaire regarding information on their right-hand pattern.
The men identified their own index-ring finger pattern using illustrations showing hands with a longer, shorter, or equal ratio.
Compared with men whose index fingers were shorter than their ring finger, men whose index fingers were longer than their ring finger had 63% less risk for developing prostate cancer.
This risk was even more reduced among men under the age of 60 years, at 87%.
"This exciting finding means that finger pattern could potentially be used to select at-risk men for ongoing screening, perhaps in combination with other factors such as family history or genetic testing," said joint senior author Ros Eeles (The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Surrey).
The fetal development of digits and differentiation of gonads is controlled by the genes HOXA and HOXD, explain the researchers in the British Journal of Cancer. "Therefore gonadal fetal products such as testosterone may influence finger morphology," they write.
This index-ring finger length relationship has also been observed in breast cancer risk, with women with a high 2D:4D ratio (indicative of higher prenatal estrogen exposure) conferring a greater risk for developing the disease, note Muir et al.
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By Sarah Guy