Frequency of Cancer in First-Degree Relatives of Patients with Cleft Lip and / or Palate in the Brazilian Population

association between nonsyndromic cleft lip and/or palate (NSCL/P) and cancers has been observed in different studies. The objective of this study was to evaluate the frequency of cancer in relatives of patients with NSCL/P. This investigation was a cross-sectional, case-controlled study, evaluating 358 patients with NSCL/P treated at a Referral Center for craniofacial deformities (case group) and 358 patients without craniofacial alterations (control group). Information concerning the gender, age and family history of cancer in first-degree relatives for both groups was obtained. The frequency of cancer was 6.4% (n=46) in the studied population, with 18 subjects in the case group (5%) and 28 (7.8%) in control. In both groups, the most frequently reported cases were those of breast, colorectal, stomach, prostate and uterus cancers, but there was no association between the two groups. There was no association with a family history of cancer among the first-degree relatives (odds ratio=0.62; 95% IC: 0.34 to 1.15), neither when the analysis was made by type of cancer. In conclusion, both epidemiological and genetic studies have suggested common etiological factors for NSCL/P and cancer. However, in this population-based study, no association between cancer and NSCL/P could be confirmed. Frequency of Cancer in First-Degree Relatives of Patients with Cleft Lip and/ or Palate in the Brazilian Population


Introduction
Nonsyndromic cleft lip and/or palate (NSCL/P) (OMIM #119530) accounts for approximately 65% of all malformations of the craniofacial region (1,2).They present an approximate incidence of 1 case per 700 live births, varying according to geographic location, ethnics and socioeconomic status of the studied population (3).Its pathogenesis, although not fully understood, involves complex molecular events that occur during embryogenesis, with the participation of multiple genes and environmental factors (4,5).
Cancer is a multi-factorial disease in which both genetic and environmental factors play significant roles.Preventive plans for decreasing cancer incidence include both the removal of environmental agents known to be carcinogens and the identification of the cancer susceptibility gene polymorphism or mutations thereof (6).
Congenital malformations and cancer may share common etiological factors (7).Co-occurrences of malformations and cancers have been seen in children as the result of both genetic and environmental causes (8).In the last few years, epidemiological studies assessed the relationship between cancer and NSCL/P in different populations [Texas, USA, Steinwachs et al., (9); Pittsburgh, USA, Menezes et al., (1); Taioli et al., (10); Latvia, Vieira et al., (11)].However, others have failed to find an association between NSCL/P and cancer (12).Thus, the objective of this study was to evaluate the frequency of cancer among relatives of patients with NSCL/P.

Material and Methods
This was a case-control cross-sectional study to evaluate the familial occurrence of cancer in first-degree relatives of patients with NSCL/P.The sampling was performed by convenience and the groups were matched concerning gender and age.The case group consisted of 358 patients with NSCL/P, all undergoing surgical rehabilitation and treated at the Reference Center for the Rehabilitation of Craniofacial Anomalies, Bauru, SP, Brazil.Patients with a history of other congenital anomalies or other genetic diseases were excluded from this group.The control group included 358 individuals seen at other clinics of the Center, without a personal or a family history of craniofacial anomalies or other congenital anomalies, and no history of consanguinity.
The clefts were categorized into 3 types, with the incisive foramen as reference ( 13): (a) cleft lip: includes complete or incomplete clefts pre foramen, uni-or bilateral; (b) cleft lip and palate: includes uni-or bilateral transforamen clefts and pre-or post foramen clefts and (c) cleft palate: includes all post foramen clefts, complete or incomplete.The patients were evaluated by professionals with a wide experience of oral cleft symptoms.
Study participants signed an informed consent and answered a questionnaire that included the following data for analysis: age, gender, history of congenital anomalies and/or CL/P, history of consanguinity and cancer.The information collected was stored in a database and analyzed using the statistical program SPSS ® version 18.0 (Statistical Package for Social Sciences for Windows, Inc., Chicago, IL, USA).Data were analyzed with descriptive statistics and binary logistic regression.The relative risk was only used for a family history of cancer to estimate odds ratios (OR) and a 95% confidence interval.To determine the association with cancers, chi-square and Fisher's Exact Test, as well as the descriptive statistics were used.It was considered an alpha of 0.05.The study was approved by the institutional Ethics Committee (Process #259/2010).

Results
Evaluating the distribution by gender and age, there was proportionality between the case and control groups, predominantly male (51.8% n=371), with 70.1% (n=502) subjects aged less than 20 years, in the studied population (Table 1).Considering the mixed nature of the Brazilian population, the ethnic distribution between cases and controls was not used for matching.The family history of CL/P in the case group was 43.9% (n=157).As to the type of cleft in the case group, 55% (n=197) were of the cleft lip and palate type; 25.1% (n=90) were of cleft lip type; 18.4% (n=66) were of cleft palate and only 1.4% (n=5) were uncommon clefts.
The frequency of cancer in first-degree relatives was only 6.4% (n=46) in the studied population, with 18 subjects in the case group (5.0%) and 28 (7.8%) in the control group.In both groups, the most frequently reported were colorectal 1.4% (n=10), breast 1.3% (n=9), uterus 1.0% (n=7), stomach 0.8% (n=6) and prostate 0.4% (n=3) cancers.For a family history of cancer in the first grade, there was no significant correlation (p=0.1;OR=0.60; 95% CI: 0.32 to 1.10), neither when the analysis was made by the type of cancer (Table 1).

Discussion
This study assessed the prevalence of cancer in family members of NSCL/P patients in the Brazilian population.The most frequently reported cancers by both groups were colorectal, breast, uterus and stomach.There were no gender differences.The frequency of cancer in first-degree relatives was 6.5% of the population studied, with 4.9% subjects in the case group and 8% in the control group, but there was no association.
In a retrospective study of NSCL/P, it was observed that 65.1% of the subjects were male and 34.8% female (14).In the results of this study, it was found that they were mostly males.In both studies, the sample was taken from a single Reference Center for Treatment and Rehabilitation of Craniofacial Anomalies, which justifies the comparison of results.Another study, evaluating Brazilian children with NSCL/P, showed prevalence of NSCL/P for males compared to females (15).In another study, the prevalence of NSCL/P among cancer survivors was higher in the case group when compared to the control group (6).The relationship between NSCL/P and cancer has been reported by several studies that identified specific genes involved in the pathogenesis of NSCL/P and that they could be part in the carcinogenesis of certain tumours.These genes serve as important determinants of risk for the occurrence of cancer (1,6).Gene modulators of fibroblast growth factor (FGF) have been associated with several cancers and it is well known that this gene participates in about 3% of cases of NSCL/P (16,17).Mutations in the inhibitory proteins (AXIN2) were also related to an increased susceptibility of colorectal cancer (18).At last, mutations in the epithelial adhesion molecule of cadherin were observed in two families, in which two or more members had hereditary diffuse gastric cancer and oral clefts (19).Mutations in the epithelial adhesion molecule, a cadherin, expressed in various types of epithelial cells, were also found in hereditary diffuse gastric cancer and the oral cleft (19).Thus, these findings suggested that common etiological mechanisms are involved in the genesis of NSCL/P and cancer (8,18,20).
Regarding most cancer-related types, it was observed in the case group an apparent excess of melanoma and testicular cancer among survivors of cancer with a CL/P family member, when compared with survivors with no family history of CL/P (6).In the present study, despite the greater frequency of colorectal cancers, breast and uterus in the case group, there was no association with a family history of cancer in first-degree relatives.Different cancers have been linked to NSCL/P and there was a higher risk of cancer in relatives with children born with oral clefts, especially for breast, primary tumors of the brain and lung cancers (21,22).Quite recently has been observed the association of oral cancer with oral clefts (23).However, this association was not confirmed in another study correlating the risk of breast cancer in families with NSCL/P (12).
In a study conducted in the USA, families with NSCL/P and controls with no history of cancer were evaluated.It also carried out molecular studies on genes in which mutations were known to be independently associated with cancer and craniofacial anomalies (10).The authors also found a high rate of transmission of the inhibitory protein of AXIS (AXIN2) in proband with NSCL/P.It may be concluded that families that present NSCL/P may have a greater probability of cancer, notably colon cancer, since this gene, when altered, leads to susceptibility of this type of malignancy (1,6).Population studies confirmed this association with breast, primary brain and lung cancers in individuals born with oral clefts (1,10,24).Recently was reported a significant association between NSCL/P and the hereditary diffuse gastric cancer syndrome.The authors highlight the importance of the historical aspects of NSCL/P to suspect occurrence of gastric malignancy (25).
The results of this study should by no means be considered conclusive and should be interpreted with caution because of the small sample size, but it deserves further investigation.Further studies should be conducted to better understand this possible correlation and the evaluation of a specific type of tumor may facilitate the understanding of the genes involved in the etiology of orofacial clefting.
In conclusion, this is the first study to be conducted for this purpose in a Brazilian population and the results do not confirm the association between NSCL/P and cancer.This preliminary finding should be confirmed by further epidemiological studies on large cohorts.Both epidemiological and genetic studies suggested common etiological factors for NSCL/P and cancer.However, the results of this study showed no association between NSCL/P and cancer.

Table 1 .
Distribution of patients with cleft lip and/or palate and controls by gender, age and associations with a family history of cancer in firstdegree relatives a Fisher's Exact test.OD: Odds ratio.CI: Confidence interval.