Serum levels of miR-29, miR-122, miR-155 and miR-192 are elevated in patients with cholangiocarcinoma

Abstract

Objectives: Cholangiocarcinoma (CCA) represents the second most common primary hepatic malignancy. Despite tremendous research activities, the prognosis for the majority of patients is still poor. Only in case of early diagnosis, liver resection might potentially lead to long-term survival. However, it is still unclear which patients benefit most from extensive liver surgery, highlighting the need for new diagnostic and prognostic stratification strategies.

Methods: Serum concentrations of a 4 miRNA panel (miR-122, miR-192, miR-29b and miR-155) were analyzed using semi-quantitative reverse-transcriptase PCR in serum samples from 94 patients with cholangiocarcinoma undergoing tumour resection and 40 healthy controls. Results were correlated with clinical data.

Results: Serum concentrations of miR-122, miR-192, miR-29b and miR-155 were significantly elevated in patients with CCA compared to healthy controls or patients with primary sclerosing cholangitis without malignant transformation. Although preoperative levels of these miRNAs were unsuitable as a prognostic marker of survival, a strong postoperative decline of miR-122 serum levels was significantly associated with a favorable patients' prognosis.

Conclusions: Analysis of circulating miRNAs represents a promising tool for the diagnosis of even early stage CCA. A postoperative decline in miRNA serum concentrations might be indicative for a favorable patients' outcome and helpful to identify patients with a good prognosis after extended liver surgery.

Fig 1. Serum levels of miR-122, miR-192, miR-29b, and miR-155 are elevated in patients with cholangiocarcinoma.

Circulating levels of miR-122 (A), miR-192 (B), miR-29b (C) and miR-155 (D) are significantly elevated in CCA patients compared to healthy controls (U-Test). ROC curve analyses show a superior diagnostic potential for miR-122 and miR-192 regarding the discrimination between CCA patient and healthy controls (E, DeLong test). The combination of two miRNAs (miR-122 and miR-192) has a superior diagnostic potential compared to either miRNA alone (F). MiR-122 has a significantly higher AUC value compared to CA19-9 (p = 0.006) and CEA (p<0.001, G, DeLong test). Serum levels of miR-122, miR-192 and miR-29b show a significant positive correlation with each other (H).

Fig 2. Circulating levels of miRNAs can discriminate between benign and malignant hepatobiliary disease.

Serum levels of miR-122 (A) and miR-192 (B) are significantly elevated in PSC patients compared to healthy controls but significantly lower compared to CCA patients (U-Test). PSC patients show similar levels of miR-29b (C) and decreased levels of miR-155 compared to healthy controls (D, U-Test). ROC curve analysis reveals that miR-122 has the highest AUC value for the discrimination between PSC and CCA patients (E). miR-122 and miR-192 show comparable AUC values when compared to standard tumor markers of CCA such as CEA and CA19-9 (F, DeLong test).

Fig 3. miRNA serum levels and patients’ prognosis.

Kaplan-Meier curve analyses show no differences regarding the overall survival between patients with preoperative (pre-OP) serum levels above or below the optimal cut-off value (A-D). High post-operative serum levels of miR-122 and miR-29b show a non-significant trend towards an impaired prognosis (E and G). High serum levels of miR-192 after tumor resection are associated with a significantly impaired long-term survival (F). Post-operative serum levels of miR-155 showed a non-significant trend towards a better outcome in patients with higher serum levels (H).

Fig 4. A strong post-operative decrease of miR-122 serum levels is associated with a good prognosis.

Kaplan-Meier curve analysis shows that patients with a strong postoperative reduction of miR-122 have a significantly better median overall survival compared to patients with increasing or only slightly decreasing postoperative levels of miR-122 (A). A similar trend of a better prognosis after tumor resection can be found for a strong postoperative decrease of miR-29b (not significant, C), whereas longitudinal changes of serum miR-192 and miR-155 do not reflect patients’ prognosis (B and D).