OLFM4 and neoplasm: And now based on gene expression patterns, it further indicated that lymph node metastatic tumor cells are more likely originated from OLFM4+SOX9+ C-type cells (PT-b), but not from OLFM4+SOX9- C-type cells (PT-a) in the primary tumor (Fig. 7A–C and Additional file 2: Fig. S10A-C).