The ADA gene encodes hydrolase, which catalyzes the hydrolysis of adenosine to inosine in the purine catabolic pathway[14, 15]. There are various mutations in the ADA gene that are related to human diseases associated with immune dysfunction, such as severe combined immunodeficiency disease (SCID), which is the result of ADA enzyme deficiency due to ADA gene mutation[16, 17]. Patients with ADA deficiency have significantly reduced T lymphocytes, B lymphocytes and NK lymphocytes, so they lack humoral and cellular immunity[18–20]. On the contrary, elevated levels of ADA enzymes are related to congenital hemolytic anemia.
Protein ADA showed a multifunctional role[21, 22]. ADA protease can catalyze the deamination of adenosine and 2-deoxyadenosine[23]. ADA protease acts as an important role in purine metabolism and adenosine homeostasis, signal regulation via extracellular adenosine, indirectly assigned to cell signaling events, and plays an active role in the regulation of activation of T cells CO in combination with DPP4 and regulates adhesion of lymphocyte epithelial cells by interactions with DPP4[24, 25]. ADA protein can improve immunogenicity of dendritic cells and improve differentiation and proliferation of CD4 + T cells by regulating expression of stimulation molecules and secretion of cytokines and chemokines[26, 27]. ADA protein also increases affinity with adenosine receptors ADORA1 and ADORA2 ligands in the form of conformational changes.ADA protein can act as an active regulator of ADORA1 and ADORA2 adenosine receptors, stimulate plasminogen activation and play a role in male fertility[28].
In the overview of data from TCGA databases, GEPIA, we tested the ADA gene in 33 different tumors.However, ADA expression was significant in 11-tumours.In eleven different tumours, we investigated the ADA gene for molecular characteristics, genetic variation and analysis of the cell pathway of gene expression.
ADA was expressed in eleven tumors.However, ADA survival data and prognosis analyses have shown that there are clear conclusions about survival and prognosis of 11 tumors.We analyzed the ADA gene survival analysis between 11-tumor types and normal tissues in the GEPIA dataset.ADA expression was related to prognosis of OS(total survival) in HNSC(P = 0).018), KIRC(P = 0.019).DFS analysis (Disease free survival) removed the relationship between ADA gene expression and prognosis for GEPIA cases KIRC(P = 0).0014), PAAD(P = 0.03), PRAD(P = 0.018).Alteration analysis of the gene shows that the frequency of ADA gene changes is between 3% and 8% in UCS, STAD, OV, HNSC, PRAD, LAML.