It therefore follows that non-tumor promoting fibroblasts (i.e., those with very low PGE2 secretion; i.e. tissue sample I) perhaps lack the ability to activate certain pathways downstream of PGE2 that modulate the balance of cytokine secretion required for CD44+/CD24−/EpCAM+ cell expansion and tumor promoting ability in vivo. Here, CD44 is linked to neoplasm.