Pregnancy loss can be caused by several factors involved in human reproduction. Although up to 50% of cases remain unexplained, it has been postulated that the major cause of failed pregnancy is an error of embryo implantation. Transmembrane mucin-1 (MUC-1) is a glycoprotein expressed on the endometrial cell surface which acts as a barrier to implantation. The gene that codes for this molecule is composed of a polymorphic tandem repeat of 60 nucleotides. Our objective was to determine if MUC-1 genetic polymorphism is associated with implantation failure in patients with a history of recurrent abortion. The study was conducted on 10 women aged 25 to 35 years with no history of successful pregnancy and with a diagnosis of infertility. The control group consisted of 32 patients aged 25 to 35 years who had delivered at least two full-term live children and who had no history of abortions or fetal losses. MUC-1 amplicons were obtained by PCR and observed on agarose and polyacrylamide gel after electrophoresis. Statistical analysis showed no significant difference in the number of MUC-1 variable number of tandem repeats between these groups (P > 0.05). Our results suggest that there is no effect of the polymorphic MUC-1 sequence on the implantation failure. However, the data do not exclude MUC-1 relevance during embryo implantation. The process is related to several associated factors such as the mechanisms of gene expression in the uterus, specific MUC-1 post-translational modifications and appropriate interactions with other molecules during embryo implantation

Several authors have investigated the malignant transformation of endometriosis, which supports the hypothesis of the pre-neoplastic state of endometriotic lesions, but there are few data about the pathways and molecular events related to this phenomenon. This review provides current data about deregulated genes that may function as key factors in the malignant transition of endometriotic lesions. In order to do so, we first searched for studies that have screened differential gene expression between endometriotic tissues and normal endometrial tissue of women without endometriosis, and found only two articles with 139 deregulated genes. Further, using the PubMed database, we crossed the symbol of each gene with the terms related to malignancies, such as cancer and tumor, and obtained 9,619 articles, among which 444 were studies about gene expression associated with specific types of tumor. This revealed that more than 68% of the analyzed genes are also deregulated in cancer. We have also found genes functioning as tumor suppressors and an oncogene. In this study, we present a list of 95 informative genes in order to understand the genetic components that may be responsible for endometriosis' malignant transformation. However, future studies should be conducted to confirm these findings. Vários autores têm estudado transformações malignas em endometriose que suportam a hipótese de um estado pré-neoplásico das lesões endometrióticas; contudo, existem poucos dados sobre as vias e eventos moleculares relacionados a este fenômeno. Esta revisão fornece dados atuais sobre genes desregulados que possam funcionar como fatores-chave para a transição maligna das lesões endometrióticas. Assim, inicialmente, estudos de expressão gênica diferencial em larga escala comparando tecido endometriótico e endométrio normal de mulheres sem endometriose foram procurados, e apenas dois artigos com 139 genes desregulados foram obtidos. Posteriormente, usando o banco de dados do PubMed, foram cruzados os símbolos de cada gene com termos relacionados à malignidade, como câncer e tumor, e 9.619 artigos foram obtidos, dos quais 444 eram estudos sobre expressão de genes associados a tipos específicos de tumor. Isto revela que mais de 68% dos genes analisados eram também desregulados em câncer. Também foram encontrados genes que funcionam como supressor tumoral e um oncogene. Este estudo apresenta uma lista de 95 genes informativos para compreender os componentes genéticos que possam ser responsáveis por transformações malignas na endometriose. Contudo, estudos futuros são necessários para confirmar estes achados.