What does the multivariable analysis conclude about the clinical use of Beclin-1?

• A. Beclin-1 is the best independent predictive biomarker for identifying dogs likely to fail adjunctive therapy, regardless of histological grade or mitotic count
• B. Beclin-1 has no predictive value
• C. Beclin-1 predicts only high-grade tumors
• D. Beclin-1 predicts only in combination with mitotic count

Answer: (A)

The key idea is that multivariable analysis tests whether a biomarker adds prognostic information above and beyond other known factors. If Beclin-1 remains significantly associated with the outcome after adjusting for histological grade and mitotic count, it is an independent predictor rather than just a surrogate for those factors. In this case, Beclin-1 is identified as the best independent predictive biomarker for identifying dogs likely to fail adjunctive therapy, and this predictive value holds regardless of histological grade or mitotic count. Practically, this means Beclin-1 provides unique risk information that can aid in risk stratification and treatment planning beyond what grade or mitotic count offer.

The other possibilities would imply no predictive value, or that Beclin-1’s predictive power is confined to high-grade tumors or only appears when combined with mitotic count. The multivariable result shows Beclin-1 adds information independently of those factors, supporting its clinical usefulness across different histologic grades and mitotic counts.