Análise da razão entre os dedos indicador e anelar (2D:4D) em pacientes com neoplasias malignas de estômago e colorretal

Abstract

The relationship between the index finger and ring finger, known as the 2D:4D ratio, has been used by researchers as a possible marker of human behavior and psychological characteristics of susceptibility to various diseases, especially those which show sex difference in their occurrence. The difference between the second and fourth finger of the hand reflects an important factor the intrauterine exposure to sex hormones, especially estrogen and testosterone. Genes that act in the differentiation of fingers in the prenatal period are also essential in the development of various organs, and mutations in these genes are related to the onset of gastric carcinogenesis and colorectal cancer. The aim of the present study was to investigate the possible relationship between the 2D:4D ratio and gastric and colorectal cancer. In all, 480 individuals participated in this study: 120 diagnosed with stomach neoplasms and 120 healthy subjects, plus 120 individuals with colorectal cancer and 120 individuals without diagnosis of this disease, paired by sex and age. Patients with the disease were assisted by the Oncology Clinic at the Santa Casa de Montes Claros, Minas Gerais, Brazil. Data collection involved taking measurements of the lengths of the ring and index fingers of the right and left hands using a digital caliper and subsequent calculation of the 2D:4D ratio. The difference between the right hand and the left hand was also obtained. Later, a database was constructed using the program SPSS™ version 20.0 for Windows™, adopting a significance level of 5%. To compare the average of the ratios between the groups, we used the Student’s t-test for the variables presenting normal distribution and the Mann-Whitnney test for those who did not have normal distribution. It may be noted that individuals diagnosed with gastric cancer had significantly higher 2D:4D proportions compared to control subjects for either hand (p< 0.0001) and individuals diagnosed with colorectal cancer had significantly lower 2D:4D proportions for right hands (p=0.0001) and left (p=0.0001) compared to individuals without the disease. These results indicate that the 2D:4D ratio is a putative marker for these neoplasms. Validation of 2D:4D proportion as a marker for these neoplasms may help, in addition, to research the classically described risk factors, and as an additional strategy in the orientation of patients at risk of developing such conditions.