Adenosine deaminase in saliva as a diagnostic marker of squamous cell carcinoma of tongue

Tongue cancer is amongst the most common and fatal types of cancers in the world. The abnormalities in purine metabolism are characteristic features of many human tumors. Little is known about the correlation between the activities of key enzymes of purine nucleotide pathway and clinical indicators of tongue cancer invasiveness and aggressiveness. Fifty patients (M: F 25:25; mean age: 55.6 years (range 45-60; SD 1.8)) with diagnosed squamous cell carcinoma of the tongue (test group) and 30 normal subjects (M: F 15:15) without any systemic disease (control group) were recruited after obtaining informed consent. All patients were staged by the TNM classification. Salivary adenosine deaminase (ADA) activity was assessed in cancerous patients (test group) and normal healthy subjects (control group). Statistically significant differences between test and control groups were observed in salivary ADA (P < 0.001). Furthermore, serum ADA levels significantly increased as the disease stage progressed from stage I to stage III of squamous cell carcinoma of the tongue in both genders (P < 0.001). Salivary ADA might be used as a diagnostic tool for early detection of squamous cell carcinoma of tongue.