BCAM (basal cell adhesion molecule) protein expression in different tumor populations.

Basal Cell Adhesion Molecule (BCAM), a receptor for laminin subunit α5, plays a crucial role in the pathogenesis of various malignancies. Notably, evidence of hypermethylation at multiple immune checkpoints in patients with low BCAM expression suggests these individuals may respond favorably to immunotherapy using ICIs (immune checkpoint inhibitors). This finding lays the foundation for the hypothesis that BCAM may serve as an important biomarker in cancer patients. To investigate this potential, we evaluated BCAM expression patterns in 3114 patients from both discovery and validation cohorts, spanning seven cancer types, using quantitative immunofluorescence (QIF). We also explored the correlation between BCAM and PD-L1 expressions within these cohorts, aiming to establish its potential predictive value for immunotherapy response. Our findings indicate that BCAM was highly expressed in ovarian (79.2%) and lung (78.5%) tumors, with lower yet significant expression in breast (37.7%), head and neck (31.3%), and bladder-urothelial tumors (27.6%). Notably, high BCAM expression was associated with better OS in NSCLC. More importantly, BCAM expression did not correlate with PD-L1 protein expression in any of these tumors, highlighting its independent predictive potential. The widespread expression of BCAM across multiple tumor types, coupled with its lack of correlation with PD-L1 expression, highlights its potential as a predictive novel biomarker across various cancer types.