Câncer no aparelho reprodutor feminino: avaliação da razão digital 2D:4D, agenesia dentária e história familiar de fissura labial e/ou palatina não sindrômica

Abstract

The digital ratio between the second and fourth digits of the hands, known as 2D:4D, has been suggested as a proxy biomarker for prenatal androgen activity and it is known as a marker associated with carcinogenic events. Cancer and congenital malformations have also been associated for they share common etiology. This study evaluated the association of the digital ratio (2D:4D), the occurrence of dental agenesis, and the family history of nonsyndromic cleft lip with or without cleft palate (NSCL±P) between women with or without cancer in the female reproductive system. Three studies were carried out, two of them case-control studies and one systematic review of the literature on the association between cancer and 2D:4D. The two case-control studies involved 105 patients with uterine or ovarian cancer (case group) and 210 clinically healthy women (control group), matched by age. On the first study, Student's t test for unpaired samples was used to compare the means of continuous variables – age, right 2D:4D (R2D:4D) and left 2D:4D (L2D:4D) – between case and control groups. A significance level of 5% (p<0.05) was adopted. In this study, women in case group presented a R2D:4D slightly higher than women in control group (p=0.062). The L2D:4D showed no statistically significant difference (p=0.222). This slight trend of statistic association between the R2D:4D and cancer in the female reproductive system suggests that women with this type of cancer probably had a higher exposure to estrogen and a lower exposure to testosterone in utero. On the second study, descriptive and comparative statistical analyzes were performed with baseline characteristics from both groups, such as age, parental consanguinity, skin color, history of dental agenesis, and family history of NSCL±P. Pearson's chi-square and Fischer exact tests and Odds Ratio (OR) with confidence interval of 95% (CI 95%) were used in order to evaluate the association of dental agenesis and the history of NSCL±P in first degree relatives between case and control groups. A significance level of 5% (p<0.05) was adopted. It was observed that 2% of women in case group and 0.98% in control group reported congenital absence of at least one tooth (1df chi-square, p=0.464; Fisher's exact test, p=0.600). In the cancer group two patients reported family history of NSCL±P while in control group there were five reports of that (1df chi-square, p=0.787; Fisher's exact test, p=1.000). The occurrence of dental agenesis in patients with cancer in the female reproductive system and the family history of NSCL±P was not significantly increased. The third study was a systematic review with 21 studies that address the association between 12 cancer and 2D:4D. Among them, sixteen (76.19%) reinforced the evidence of 2D:4D as an important biomarker associated with various types of cancer. Although most studies point to a significant association between 2D:4D and cancer, the methodological differences in the studies involving this association with certain types of cancer limited the elucidation through meta-analysis. Despite these limitations, 2D:4D remains a biomarker of prenatal exposure to androgens which may have a predictive value in the risk of some types of cancer.