Soeno T, Katoh H, Ishii S, et al. - Researchers investigated the clinical significance of immature myeloid-derived immune cells in patients with gastric cancer (GC) who underwent curative gastrectomy with curative lymphadenectomy and were administered S-1 (tegafur/gimeracil/oteracil) postoperatively. Among curatively resected stage II and III GC, they observed dramatically worse prognosis among patients with high CD33+ cell counts in primary tumor (5-y recurrence-free survival 29.0%) than that of the counterparts (79.4%). They identified an independent predictive value of high CD33+ cell counts for poor prognosis in stage II/III. Recruitment of CD33+ immature myeloid cells was identified as a significant predictor of hematogenous recurrences in curatively resected advanced GC. In view of these results, they suggest focusing on CD33+ myeloid-derived cells as a novel approach to tackle advanced GC.