Numerous studies have proved that abnormal expression of miRNAs is closely associated with the pathogenesis and expansion of cancer by post-transcriptionally affecting the expression of criticalgenes. So, due to the unique miRNA-expression profile for each tumor and the absence of complex transcriptional and translational alterations compared to mRNAs and proteins, the usage of miRNAs asbiomarkers for cancer is very important. Recent investigations have confirmed the importance use of tumor-specific miRNAs as diagnostic indications for cancer in body fluids. We searched about this subjects in Google Scholars, Web of Sciences, PubMed and Scopus then found 10 articles related to our subject and we explained them in the results. A study showed a panel of four miRNAs in the salivaof patients with oral squamous-cell carcinoma compared with healthy controls; miR 125a and miR 200a were existing in significantly lower levels in the saliva of the cancer patients. In another study, increased miR 126, miR 152, and miR 182 were discovered in urine samples from patients with bladder cancer. Head and neck squamous cell carcinoma (HNSCC) is the sixth most serious cancer in the world. miR-9(P <0.0001), miR-134 (P <0.0001) and miR-191 (P <0.001) were differentially expressed among saliva from HNSCC patients and healthy controls. The saliva-derived miRNAs miR-9, miR-134 and miR-191may serve as new biomarkers to constantly identify HNSCC. Zhu and colleagues showed that overexpression of miR-9 may be related to colorectal carcinoma metastasis by increasing cell motility.In addition, it was noted that, when miR-9 was over-expressed in non-metastasising breast carcinoma cells. Also, Hui and colleagues reported that miR-9 and miR-9 were powerfully related to HPV/p16-status in oropharyngeal carcinomas. More recent studies have reported that miR-134 is contributed in tumor repression in prostate and lung cancers, and that its down-regulation is associated with drugresistance. Furthermore, miR-191 was showed to exhibit a tissues specific expression pattern, and to be over-expressed in colon, lung, pancreas, prostate and stomach cancers. also, Esophageal cancer (EC) is the eighth most serious cancer and 6th causing of cancer mortality. 4 miRNAs (miR-10b, miR-144, miR-21, and miR-451) were meaningfully upregulated in EC group saliva supernatants. Biagioni F, and colleagues reported that microRNA-10b is a master manager of breast cancer cell proliferation and is downregulated in tumoral models versus matched peritumoral counterparts, they also propose thatrestoration of microRNA-10b expression might have treatment potential. Other studies indicated that miR-3679-5p major downregulation in the pancreatic cancer group. While miR-940 showed important upregulation in pancreatic cancer. Salivary miR-3679-5p and miR-940 possess good biased power to detect pancreatic cancer, with notable specificity and sensitivity. Some evidences showed that twomiRNAs (miR-125a and -200a) showed decreased levels in saliva with oral cancer. MicroRNAs are abundant in all the body fluid types tested. Fluid type–specific miRNAs may have functional charactersrelated to the surrounding tissues. Furthermore, the changes in miRNA spectra detected in the body fluids samples from different patients proves the capability for using concentrations of specific miRNAs in body fluids as biomarkers for diagnosing and prognosing numerous physio pathological conditions.