Table 1.

Search strategy in PubMed database.

Number	Search terms
#1	miRNA-21 [Title/Abstract]
#2	microRNA-21 [Title/Abstract]
#3	miR-21[Title/Abstract]
#4	hsa-miR-21[Title/Abstract]
#5	OR/1-4
#6	Breast Neoplasms [MeSH]
#7	Breast Cancer[Title/Abstract]
#8	Breast Tumors[Title/Abstract]
#9	Cancer of Breast[Title/Abstract]
#10	Cancer of the Breast[Title/Abstract]
#11	Human Mammary Carcinoma[Title/Abstract]
#12	Mammary Carcinoma, Human[Title/Abstract]
#13	Mammary Neoplasm, Human[Title/Abstract]
#14	Mammary Neoplasms, Human[Title/Abstract]
#15	Neoplasms, Breast[Title/Abstract]
#16	Tumors, Breast[Title/Abstract]
#17	Breast Neoplasm[Title/Abstract]
#18	Breast Tumor[Title/Abstract]
#19	Cancer, Breast[Title/Abstract]
#20	Carcinoma, Human Mammary[Title/Abstract]
#21	Carcinomas, Human Mammary[Title/Abstract]
#22	Human Mammary Carcinomas[Title/Abstract]
#23	Human Mammary Neoplasm[Title/Abstract]
#24	Human Mammary Neoplasms[Title/Abstract]
#25	Mammary Carcinomas, Human[Title/Abstract]
#26	Neoplasm, Breast[Title/Abstract]
#27	Neoplasm, Human Mammary[Title/Abstract]
#28	Neoplasms, Human Mammary[Title/Abstract]
#29	Tumor, Breast[Title/Abstract]
#30	OR/6–29
#31	survival[Title/Abstract]
#32	prognos∗[Title/Abstract]
#33	OR/31–32
#34	#5 AND #30 AND #33