“…Even though p16 evaluation was not available in the entire cohort, this emphasises the role of other biological features to help clarify the cause of radioresistance in anal cancer. Hypoxia is associated with increased radioresistance in solid tumours [25] and might play a role in explaining radioresistance in anal cancer [26] . Investigating the biological features, for a better understanding of radioresistance and treatment failure, is highly relevant for developing new intensified treatment options.…”