Abstract <p>A possibility of using a quantum-dot-based “electronic nose” diagnostic device for revealing the skin gas profile of cancer patients is considered. An assessment of the skin volatile compound profile of patients diagnosed with cancer during their hospital stay and its comparison with the gas profile of a group of apparently healthy volunteers allowed us to reveal characteristic parameters indicative of the progression of pathological processes. A difference in the composition of the skin volatile compound mixture between the apparently healthy and cancer patients is demonstrated by comparing the integrated signal from the sensor array and a matrix of calculated parameters. A theoretical model is proposed for estimating the probability of assignment to cancer patients based on the signals of a sensor array in measuring an exhaled breath from the forearm skin. The validity of the proposed theoretical model for deciding on the presence/absence of the disease is confirmed by a reverse evaluation method using a group of 20 volunteers. The metrological reliability of clustering into groups is assessed: the accuracy and sensitivity are 100% across the sample.</p>