**1. Introduction**

Hepatocellular carcinoma is one of the most aggressive human cancers. The total oncological mortality is decreasing in many developed countries, e.g., it has been reduced by 23% since 1991 in the United States of America (USA). In contrast, death rate of HCC is increasing, along with the incidence of this tumour [1, 2]. Positive changes are expected due to risk factor eradication by vaccination against hepatitis B and improved treatment of chronic hepatitis C. The treatment of HCC has also developed significantly, including radiofrequency ablation, transarterial chemoembolisation, liver resection and transplantation as well as molecular targeted treatment by sorafenib. However, SEER-based analysis has revealed that survival has improved in early but not in advanced cases [2]. Thus, timely diagnostics remain an important goal.

(to shoulder) or complications that lead to peritoneal irritation (bleeding, bile accumulation in the peritoneum perforation of the internal organs). Few death cases have been reported after

Innovative Blood Tests for Hepatocellular Carcinoma: Liquid Biopsy and Evaluation of Systemic…

http://dx.doi.org/10.5772/intechopen.76599

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Non-invasive means of HCC diagnostics would be beneficial. Two promising pathways include so-called liquid biopsy by microRNA analysis in blood and assessment of tumourinduced systemic inflammatory reaction (SIR). MicroRNA spectrum might have diagnostic and prognostic value. Regarding SIR, prognostic aspects have been studied and appear as

MicroRNAs (miRNAs) are small, double-stranded, non-coding RNA molecules consisting of approximately 22 nucleotides. MiRNAs regulate gene expression at the post-transcriptional level [4, 5] acting as large-scale molecular switches. MiRNAs are found not only in cells but also in body fluids. Due to the stable and relatively simple structure, these molecules are good biomarkers for diagnostic and prognostic evaluation complying with the idea of so-called liquid biopsy—a patient-friendly blood test bringing the same information as a biopsy. In order to increase the diagnostic value of such tests, panels of miRNAs have been advocated. However, the biological course of HCC cause a possible pitfall in the elaboration of such diagnostic tests: as HCC mainly arise on the background of liver cirrhosis, inflammatory or metabolic liver diseases, these preceding pathologies can also alter the levels of miRNAs.

MiRNA-122 is attractive for its wide expression in liver tissues suggesting significant role in liver functions. MiRNA-122 is upregulated in serum of HCC patients and downregulated in HCC tissues suggesting specific excretion of miRNA-122 in blood by HCC. Although miRNA-122 shows high specificity and sensitivity for HCC in comparison with healthy controls (83.3 and 81.6%, respectively), levels of miRNA-122 change in other liver pathologies as well, limit-

Comparing HCC patients with those having hepatitis B or liver cirrhosis, serum levels of exosomal miRNA-18a, miRNA-221, miRNA-222 and miRNA-224 were increased, while miRNA-101, miRNA-106b, miRNA-122 and miRNA-195 were decreased. MiRNA-16 was decreased in HCC, and the levels significantly differed from those found in hepatitis C virus (HCV) infection because chronic viral hepatitis C and non-alcoholic fatty liver disease are characterised by the contrary changes—increase in miRNA-16. MiRNA-21 is characterised by positive characteristics in meta-analysis showing specificity and sensitivity for HCC diagnosis of 84.8 and 81.2%, respectively. The changes of miRNA-21 serum levels in HCC patients significantly differ from cases of chronic hepatitis; however, other malignant tumours can also yield higher

Several panels of miRNAs have been recommended. Exploring nine serum miRNAs (miRNA-21, miRNA-30c, miRNA-93, miRNA-122, miRNA-125b, miRNA-126, miRNA-130a, miRNA-193b and miRNA-222) in HCC and chronic viral hepatitis C patients, nine markers were decreased in chronic hepatitis C *versus* healthy controls, while seven markers (miRNA-21,

liver biopsy: 0.01–0.1% of patients [3].

ing the diagnostic application [6].

serum concentration of miRNA-21 [7].

promising adjunct how to select patients for treatment.

**2. miRNAs in the diagnostics of hepatocellular carcinoma**

Most of the hepatocellular carcinoma cases develop on the background of liver cirrhosis or chronic inflammatory liver disease in precirrhotic stage, e.g. chronic viral hepatitis B or C, alcohol-induced or autoimmune liver disease or non-alcoholic steatohepatitis (NASH). This might facilitate the diagnostics by screening of the risk population. Nowadays, screening by ultrasonography and non-invasive radiological diagnosis by the means of computed tomography or magnetic resonance imaging is the mainstay of HCC diagnostics. However, the radiological findings in early cases can be difficult to interpret. Biopsy is indicated in such controversial cases.

However, the biological course of HCC can result in diagnostic difficulties even in biopsy. HCC frequently develops in a dysplastic cirrhotic nodule. Such early HCC is typically well differentiated. Over time, it progresses to advanced dedifferentiated HCC. The resulting heterogeneity can lead to diagnostic problems and failures in biopsy due to sampling errors. For instance, if a small nodule seemed suspicious but not overtly malignant by radiological imaging, leading to biopsy, the differential diagnosis between dysplastic nodule and HCC will frequently imply the necessity to distinguish between premalignant process and welldifferentiated tumour, usually lacking marked cell atypia or clear-cut invasion. In addition, both processes can be adjacent in the tissues. Consequently, early diagnostics of HCC is not straightforward even in biopsy.

In addition, biopsy can cause complications, including arterial hypotension, bleeding, pneumothorax, haemothorax, haemobilia, acute pancreatitis, visceral perforation, biliary fistulas, sepsis and needle breakage. Arterial hypotension is seen frequently (1.1–4.0%), mostly due to vasovagal reaction. In few cases, falling arterial blood pressure might indicate bleeding, if it is unusually severe. Bleeding can develop in the liver tissues or in the peritoneal cavity. It is seen in 4.5% of patients and is more frequent if INR is elevated: frequency of bleeding was 3.3% in patients having INR 1.3–1.5 and 7.1% among those who had INR > 1.5. Pneumothorax and haemothorax have been reported in 0.35 and 0.18% of patients, if the needle has accidentally passed through lung or diaphragmatic and intercostal blood vessels. Haemobilia has been described in 0.1% of patients and can induce acute pancreatitis via biliary obstruction. The frequency of visceral perforation, biliary fistulas, sepsis and needle breakage is 0.01% each. In addition, biopsy can result in pain, experienced in up to 84% of patients. In 40% of cases, pain lasts for 24 hours. It is attributable to skin and liver capsule damage, viscerosomatic irradiation (to shoulder) or complications that lead to peritoneal irritation (bleeding, bile accumulation in the peritoneum perforation of the internal organs). Few death cases have been reported after liver biopsy: 0.01–0.1% of patients [3].

Non-invasive means of HCC diagnostics would be beneficial. Two promising pathways include so-called liquid biopsy by microRNA analysis in blood and assessment of tumourinduced systemic inflammatory reaction (SIR). MicroRNA spectrum might have diagnostic and prognostic value. Regarding SIR, prognostic aspects have been studied and appear as promising adjunct how to select patients for treatment.
