ADA and cancer: 2001; Gupta and Nair 2006). It is localised in many tissues, including the lymphoid system, gastrointestinal tract, spleen, skin, brain and kidney. ADA is expressed in almost all mammalian tissues and plays a critical role in the differentiation and maturation of the immune system. ADA is used as a crucial biomarker for assessment of several diseases, such as cancer and pulmonary diseases (Bradford et al. 2017; Beyazit et al. 2012; Flinn and Gennery 2018; Ebrahimi‐Rad et al. 2018).