Table 3.

Representative miRNAs from patient tumor specimens as predictive markers for treatment outcome in cancer therapy

Cancer type	miRNA dysregulation	Chemotherapeutic outcome prediction	Reference
Metastatic breast cancer	miR-26a ↑	- Multivariate analysis revealed that miR-26a and CDC2 (cell cycle regulator) are an optimal set of markers associated with favorable outcome on tamoxifen therapy, independently of traditional predictive factors (menopausal status, ER & PgR mRNA expression)	[75]
		- Mechanistic analysis showed that miR-26a repressed EZH2 to upregulate ER, thereby enhancing sensitivity to anti-estrogen therapy
CRC	miR-181b↓ & let-7 g↓	Associated with responsiveness to 4th generation fluoropyrimidine-based adjuvant therapy	[76]
CRC	miR-215↑	- miR-215 level generally downregulated in clinical CRC specimen	[77]
		- ↑miR-215 caused chemoresistance of HCT116 to methotrexate and tomudex
		- No impact on treatment outcome from cisplatin and doxorubicin
		- High level of miR-215 was found in CRC stem cells
Metastatic CRC	miR-146b-3p↑ & miR-486-5p↑	- miRNAs level found to be more abundant in patients with mutant KRAS	[78]
		- Predictive of resistance to cetuximab (EGFR targeting monoclonal antibody)
Metastatic CRC	miR-200b ↑	- In KRAS mutated tumors, ↑ miR-200b and ↓ miR-143 were associated with a good PFS in patients on cetuximab	[79]
	miR-143 ↓
		- In wild-type KRAS patients, miRNA expression did not correlate with PFS in a multivariate model
GBM	5-miRNAs signature (miR-181d, miR-518b, miR-524-5p, miR-566, miR-1227)	- Patients who had low risk scores from the 5-miRNA signature and received temozolomide treatment had better survival	[80]
		- Useful for identifying patients for more aggressive therapy
Hepatocellular carcinoma	miR-26↓	Lower miR-26 is associated with shorter overall survival but a better response to interferon therapy	[81]
NSCLC	miR-21 ↑	Increased miR-21 in patients not responding to platinum-based chemotherapy	[82]
Lung cancer	miR-128b LOH	Predictive of clinical response and prolonged survival following gefitinib treatment	[83]
Ovarian cancer	let-7i↓	Predictive of resistance to cisplatin	[84]
Pancreatic cancer	miR-21↑	- Predictive of resistance to gemcitabine, docetaxel, temozolomide and 5-fluorouracil	[85,86]
		- Associated with shorter overall survival in the metastatic and adjuvant setting
Pancreatic ductal adenocarcinoma	miR-10b ↓	Lower levels of miR-10b is associated with improved response to multimodality neoadjuvant therapy. Likelihood of surgical resection, delayed time to metastasis and increased survival	[87]

Abbreviations: CRC = colorectal cancer; EGFR = epidermal growth factor receptor; ER = estrogen receptor; GBM = glioblastoma multiforme; LOH = loss of heterozygosity; NSCLC = non-small cell lung cancer; PFS = progression-free survival; PgR = progesterone receptor.