Lack of expression of B2M is associated with a better clinical outcome in advanced disease. Kaplan-Meier curves of cases with clinical information show that positivity for B2M by immunohistochemistry in the HRS cells associates with a poor progression-free survival (PFS) and overall survival (OS), as compared with cases that lack B2M expression in the entire cohort (top row). The middle row shows Kaplan-Meier curves for patients with stages I and II cHL; the bottom row shows Kaplan-Meier curves for patients with stages III and IV cHL. Among patients with advanced stage, but not in patients with early-stage cHL, positivity for B2M by immunohistochemistry in the HRS cells showed a trend for poor OS, as compared with cases that lack B2M expression. NS, not significant.