A comparative study of multiple instance learning methods for cancer detection using T-cell receptor sequences

• Published in: Computational and structural biotechnology journal 2021-01, Vol.19, p.3255-3268
• Main Authors: Xiong, Danyi, Zhang, Ze, Wang, Tao, Wang, Xinlei
• Format: Article
• Language: English
• Subjects: Binary classification; Primary instance; Review; T-cell receptor; Weakly supervised learning; Witness rate
• ISSN: 2001-0370; 2001-0370
• DOI: 10.1016/j.csbj.2021.05.038

[Display omitted] •We applied multiple instance learning (MIL) for cancer detection using TCR sequences.•An updated review of MIL methods and their categorization are provided.•Bag-space MIL methods tend to outperform instance-space and embedded-space methods.•Future development is needed for MIL methods using the primary instance assumption. As a branch of machine learning, multiple instance learning (MIL) learns from a collection of labeled bags, each containing a set of instances. The learning process is weakly supervised due to ambiguous instance labels. Since its emergence, MIL has been applied to solve various problems including content-based image retrieval, object tracking/detection, and computer-aided diagnosis. In biomedical research, the use of MIL has been focused on medical image analysis and molecule activity prediction. We review and apply 16 methods to investigate the applicability of MIL to a novel biomedical application, cancer detection using T-cell receptor (TCR) sequences. This important application can be a viable approach for large-scale cancer screening, as TCRs can be easily profiled from a subject’s peripheral blood. We consider two feasible data-generating mechanisms, and for the purpose of performance evaluation, we simulate data under each mechanism, where we vary potentially important factors to mimic realistic situations. We also apply the methods to sequencing data of ten cancer types from The Cancer Genome Atlas, as an early proof of concept for distinguishing tumor patients from healthy individuals via TCR sequencing of peripheral blood. We find that given an appropriate MIL method is used, satisfactory performance with Area Under the Receiver Operating Characteristic Curve above 80% can be achieved for five in the ten cancers. Based on our numerical results, we make suggestions about selection of a proper method and avoidance of any method with poor performance. We further point out directions of future research as well as identify a pressing need of new MIL methodologies for improved performance (for some cancer types) and more explainable outcomes.