Related Experiment Video
Updated: Nov 30, 2025

Cell-Free DNA Integrity Analysis in Urine Samples
Published on: January 5, 2017
The second to fourth digit ratio (2D:4D): A risk factor of bladder cancer in men
Tianqi Wang1, Dongxu Zhang1, Kai Sun1
1Department of Urology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong, China.
Background:
Exposure to prenatal sex steroids as indicated by the ratio of the second to fourth digit length (2D:4D) has been linked to the risk of onset of cancer, while sex steroids may expand the gender disparity in bladder cancer (BC) morbidity.
Aim:
To explore the association between 2D:4D ratio and BC risk.
Subjects:
307 bladder cancer patients and 321 cancer-free individuals.
Outcome Measures:
Relationships between 2D:4D and incidence of bladder cancer.
Results:
For males, a lower 2D:4D ratio of both hands was obtained in the BC group, relative to the control group (left hand: 0.940 ± 0.031 vs. 0.954 ± 0.024, t = -4.72, p < 0.001, Cohen's d = 0.491 and right hand: 0.939 ± 0.031 vs. 0.952 ± 0.022, t = -4.493, p < 0.001, Cohen's d = 0.511). In females, no differences in the 2D:4D ratio were observed between the BC and control groups (p > 0.05). Correlation analysis between 2D:4D ratio and pathological index found no correlation among the BC grade or stage (p > 0.05).
Conclusion:
Men with BC have a lower 2D:4D ratio compared with healthy men. Therefore, having a low 2D:4D ratio is a risk factor for BC in men. Prenatal exposure to sex steroids might play a role in the etiology of BC, which could partially explain the gender disparity in the prevalence of BC.
Related Concept Videos
Disorders of the Male Reproductive System
Prostate disorders are another major concern. These conditions can impair urinary flow due to the prostate's location around the urethra....
Odds Ratio
Nursing Assessment of the Genitourinary System I: Health History
Anatomy of the Genitourinary System II: Bladder and Urethra
Imaging Studies IV: Magnetic Resonance Imaging
Urinary Bladder
In males, the bladder is situated in front of the rectum, while in females, it is positioned anterior to the vagina and uterus. The bladder floor contains an inverted triangular area called the trigone, defined by the two ureteric...

