Embodiments described herein provide a neural network based cancer detection and subtyping tool for predicting the presence of a tumor, its tissue of origin, and its subtype using small RNA sequencing (smRNA-seq) data, for example, the oncRNA count data. Specifically, the AI-based cancer detection and subtyping tool uses variational Bayes inference and semi-supervised training to adjust for batch effects and learn a low dimensional distribution explaining biological variability of the data. A method is also provided for determining the likely subtype(s) in a cancer sample.