Table 2.

Signal transmission between stromal cells and tumor cells.

Disease	Stromal cells	Drug resistance	Exosomal RNA	Mechanism/pathway	References
Gastric cancer	M2 macrophages	Cisplatin	miR-21	PTEN-PI3K- Akt	(50)
Gastric cancer	MSCs	5-fluorouracil		CaM-Ks/Raf/MEK/ERK	(51)
Multiple myeloma	Patients’ peripheral blood	Bortezomib	FFAR1/SP9/HIST1H2BG/ITIH2	mTOR/cAMP/PI3K-Akt	(52)
Colorectal cancer	Fibroblasts	5-fluorouracil Oxaliplatin		Promoted percentage, clonogenicity and tumor growth	(53)
Breast cancer	Stromal cells		5’-triphosphate exoRNA	STAT1/NOTCH3	(54)