SPP1 and neoplasm: A recent single cell sequencing analysis of immune and stromal populations in 18 colorectal tumors identified a proangiogenic, CAF-enriched, tumor-promoting SPP1+ tumor-associated macrophage population (TAM).45 It is possible that our study identified SPP1 expression on tumor-promoting TAM which drive therapy resistance, in which case specific targeting of this population during rectal cancer radiotherapy is worthy of further study.