Fructose-bisphosphate Aldolase C Expression is Associated with Poor Prognosis and Stemness in Gastric Cancer.

Gastric cancer (GC) is the third leading cause of cancer-related deaths in Japan, underscoring the urgent need for deeper insights into its pathogenesis. Spheroids provide a more realistic and versatile model for studying cancers and cancer stem cells (CSCs). While fructose-bisphosphate aldolase C (ALDOC) has been identified in colorectal cancer spheroids, its role in GC has remained largely unexplored. This study aimed to elucidate the role of ALDOC in GC by performing single-cell and functional analyses of GC spheroids and cell lines, along with immunohistochemistry of 127 GC samples to assess its correlation with CSC markers. Our single-cell analysis revealed upregulation of ALDOC in spheroids, with pseudotime analysis indicating that ALDOC-expressing cells were predominantly undifferentiated and co-expressed LGR5 and CD44. Further investigation into cell-cell interactions suggested that the stem cell state may be maintained by WNT, BMP, and EGF signaling. Functional assays demonstrated that ALDOC knockdown led to a marked reduction in the growth, invasiveness, and spheroid colony formation capacity of GC cell lines. Clinically, ALDOC was detected in the cytoplasm of 56.7% (72/127) of GC cases, and high ALDOC expression was significantly associated with poor overall survival (p < 0.01), and was an independent prognostic factor. Moreover, a significant association between ALDOC and CD44 expression in GC (p = 0.031). Conclusively, our findings identify ALDOC as a crucial prognostic marker and provide new insights into GC pathogenesis.