Breast cancer is the most common cancer among Egyptian females accounting for 37.7% of all cancer cases. FoxP3 gene is an essential transcription factor in regulatory T cells, its expression affects the proliferation of T reg cells and alters disease susceptibility. Several studies with variable results had been carried out on Foxp3 polymorphisms of the promoter region in different ethnic groups but not in Egyptians. In the present study, we evaluated two promoter polymorphisms to find any association with breast cancer.
Using SSP and PCR-RFLP to identify genotypes of Foxp3 rs3761548 and for rs3761549 respectively.
With rs3761548 the most prevalent genotype found was AC genotype followed by CC and AA and for (rs3761549) it was TT followed by CT & CC. Her2 and CA19-5 were associated with risk of metastasis prediction.
We concluded that no significant association was found between Foxp3 SNPs and risk of breast cancer.
Keywords; breast cancer; foxp3; gene polymorphism.
The most common cancer among Egyptian females is Breast cancer accounting for 37.7% of their total. It is also the cause of cancer-related mortality accounting for 29.1% of their total 1.
Both the innate and adaptive immune systems play a role in preventing relapse in women with breast cancer. The players in this fight are T cells, T regulatory cells, natural killer cells, and their cytokines. The immune system status affects cancer prognosis. Studies support the hypothesis that the immune system has a role in breast cancer etiology. Immunomodulatory therapy has an important role in breast cancer as a treatment 2.
Cytokines produced by T lymphocytes are responsible for a powerful immune response. Solid tumors are associated with T-helper type 2 (Th2) cytokine and T-helper 1 (Th1) cells in inducing inflammation that inhibits tumor growth (3).
Regulatory T cells are cells that inhibit T helper response have CD4+ and CD25 hi and express the transcription factor Foxp3 and are responsible for maintaining self-tolerance so mutations of Foxp3 causes decreased T reg and increase the risk of autoimmune disease (4).
In cancer, T reg cells may be induced by tumors to inhibit the immune response against tumor antigens. In humans, cancer induces peripheral T reg to be sensitive to apoptosis (5).
Experimental studies have shown that T reg cells expressing foxp3, transforming growth factor ? (TGF-?), and IL-10 help tumor to inhibit the normal immune response against it. In addition, studies have shown that T reg cells are increased in the peripheral blood and in the tumor microenvironment in humans with breast adenocarcinomas (6).
Several studies in Asian population have been conducted to investigate any association of FOXP3 promoter polymorphisms, rs3761549, and rs3761548, with breast cancer however, no association have yet been found (7,8).
Patients and study design:
This study was approved by the Mansoura faculty of medicine. The ethical committee (IRB) code number is R16.07.47, Participants of the study were breast cancer patients who were recruited to the Mansoura Oncology Cancer Center from 2015 to 2016.
3 ml blood from each patient had been collected in tubes containing EDTA and stored at -20°C until the relevant assays were conducted. Information on cancer diagnosis, disease stage (tumor-node-metastasis), cancer treatments, and estrogen, progesterone and human epidermal growth factor receptor-2 (HER-2) receptors status, also CA 15.3 levels were abstracted from medical charts data seen in tables (1,2&3).
Genotyping: Genomic DNA was extracted from whole blood using DNA purification kit (Qiagen, Inc., Valencia, CA, USA) and stored at -20°C until further use. Using SSP for rs3761548 and PCR-RFLP for rs3761549, FOXp3 gene alleles were amplified by same PCR conditions used in (8).
For rs3761548, a band at 209 base pair (bp) is an A allele, band at 397 bp for C allele with a general product at 564 bp.
Enzymatic Digestion of rs3761549 PCR product of fox at 388 bp, was 308 and 80 bp for wild-type (CC) and three bands for (CT) genotype.
SPSS software version 16 was used to calculate percentages, mean, and SD Chi-square was applied to compare the allele and genotype frequencies between the patients and controls and logistic regression analysis to identify the risk associated with genotypes. A p-value