Elevation of cytokeratin 19 fragment in serum in patients with hepatoma: its clinical significance

Predictive Value of Serum CYFRA 21-1 and CK19-2G2 for Tumor Aggressiveness and Overall Survival in Hepatitis C-Related Hepatocellular Carcinoma Among Egyptians: A Prospective Study

PURPOSE

Cytokeratin 19 fragment 21-1 (CYFRA 21-1) and cytokeratin 19 fragment 2G2 (CK 19-2G2) are two soluble fragments of cytokeratin 19 (CK 19) that can be detected in serum. CK 19-positive hepatocellular carcinoma (HCC) is characterized by an aggressive behavior and a poor outcome. This study aimed to assess the prognostic value of serum CYFRA 21-1 and CK 19-2G2 in predicting tumor aggressiveness and overall survival (OS) in patients with hepatic C virus (HCV)-related HCC.

METHODS

The current study included 138 patients with HCV-related HCC recruited from the Hepatobiliary and Interventional Radiology Units at Alexandria's main university hospitals and 40 healthy individuals as controls. Patients were assessed for clinical, radiological tumor characteristics, and aggressiveness index. Baseline serum CYFRA 21-1 and CK 19-2G2 levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Elevated CYFRA 21-1 levels were associated with tumors size ≥ 5 cm (p < 0.001), malignant portal vein thrombosis (mPVT) (p < 0.001), distant metastasis (p = 0.030), ill-defined/infiltrative pattern (p = 0.010), and aggressiveness index > 4 (p = 0.045). Elevated CK19-2G2 levels were not associated with any clinical or radiological characteristics. Either or both elevated serum CYFRA 21-1 and CK 19-2G2 in combination with alpha-feto protein (AFP) ≥ 400 ng/ml have a better predictability for mPVT and ill-defined/infiltrative patterns (sensitivity (10-25%) and specificity (96-100%)). Elevated levels of CYFRA 21-1, CK 19-2G2, or AFP ≥ 400 ng/ml were associated with decreased 1-year OS.

CONCLUSIONS

Either or both elevated serum CYFRA 21-1 and CK 19-2G2 levels when added to AFP ≥ 400 ng/ml are specific but less sensitive biomarkers for predicting tumor aggressiveness. These biomarkers can be used independently to predict reduced 1-year OS in Egyptian patients with HCV-related HCC.

Clinico-Radio-Pathological and Molecular Features of Hepatocellular Carcinomas with Keratin 19 Expression

Hepatocellular carcinoma (HCC) is a heterogeneous neoplasm, both from the molecular and histomorphological aspects. One example of heterogeneity is the expression of keratin 19 (K19) in a subset (4-28%) of HCCs. The presence of K19 expression in HCCs has important clinical implications, as K19-positive HCCs have been associated with aggressive tumor biology and poor prognosis. Histomorphologically, K19-positive HCCs demonstrate a more infiltrative appearance, poor histological differentiation, more frequent vascular invasion, and more intratumoral fibrous stroma than K19-negative conventional HCCs. From the molecular aspect, K19-positive HCCs have been matched with various gene signatures that have been associated with stemness and poor prognosis, including the G1-3 groups, S2 class, cluster A, proliferation signature, and vascular invasion signature. K19-positive HCCs also show upregulated signatures related to transforming growth factor-β pathway and epithelial-to-mesenchymal transition. The main regulators of K19 expression include hepatocyte growth factor-MET paracrine signaling by cancer-associated fibroblast, epidermal growth factor-epidermal growth factor receptor signaling, laminin, and DNA methylation. Clinically, higher serum alpha-fetoprotein levels, frequent association with chronic hepatitis B, more invasive growth, and lymph node metastasis have been shown to be characteristics of K19-positive HCCs. Radiologic features including atypical enhancement patterns, absence of tumor capsules, and irregular tumor margins can be a clue for K19-positive HCCs. From a therapeutic standpoint, K19-positive HCCs have been associated with poor outcomes after curative resection or liver transplantation, and resistance to systemic chemotherapy and locoregional treatment, including transarterial chemoembolization and radiofrequency ablation. In this review, we summarize the currently available knowledge on the clinico-radio-pathological and molecular features of K19-expressing HCCs, including a detailed discussion on the regulation mechanism of these tumors.

Proteomics analysis of protein expression and specific protein oxidation in human papillomavirus transformed keratinocytes upon UVB irradiation

Increasing evidence supports the role of oxidative stress in cancer development. Ultraviolet (UV) irradiation is one of the major sources of oxidative stress through the generation of reactive oxygen species (ROS). Besides the physiological function of ROS in cellular homeostasis, accumulating reports suggest that ROS are involved in all stages of multistep cancer development. In order to investigate the involvement of oxidative damage into the mechanisms of tumour progression, we used a parallel proteomic approach to analyse the protein expression profile and to identify oxidatively modified proteins in human papillomavirus (HPV)-transformed keratinocytes (HK-168 cells) upon ultraviolet B (UVB) exposure. The HK-168 cells were obtained from normal human epidermal keratinocytes transfected with the whole genome of the high-risk HPV type 16, unanimously recognized as an etiological agent of cervical carcinoma. Because of its year-long latency, this tumour offers a convenient model to study the role of environmental concurring agents in the multistep malignant progression. By the protein expression profile, we identified 21 proteins that showed different expression levels in HK-168 cells treated with UVB in comparison with untreated cells. Focusing on the oxidative modifications occurring at the protein level, we identified five proteins that showed elevated protein carbonyls levels: alpha-enolase, heat shock protein 75, annexin 2, elongation factor Tu and elongation factor gamma. Our results indicate that UVB-induced oxidative stress perturbs the normal redox balance and shifts HPV-transformed keratinocytes into a state in which the carbonylation of specific proteins is systematically induced. We suggest that UVB-induced modulation of protein expression combined with oxidative modification lead to protein dysfunction that might contribute to the malignant progression of transformed cells.

Clinical significance of serum cytokeratin-19 fragment (CYFRA 21-1) in hepatocellular carcinoma

BACKGROUND/PURPOSE

CYFRA 21-1, a soluble fragment of cytokeratin 19, is increased in serum in some patients with hepatocellular carcinoma, but the clinical significance of this increase is still unknown.

METHODS

Serum concentrations of CYFRA 21-1 were measured in 240 patients with hepatocellular carcinoma prior to hepatic resection. The relationships between serum CYFRA 21-1 concentrations and clinicopathologic features were analyzed.

RESULTS

The sensitivity of CYFRA 21-1 as a test for hepatocellular carcinoma was 18.8%. Serum CYFRA 21-1 was significantly higher in patients with portal vein tumor thrombus, and serum CYFRA 21-1 increased with the progression of portal vein tumor thrombus. Tumor size was related to serum CYFRA 21-1, but there were no significant correlations between serum CYFRA 21-1 concentrations and tumor differentiation or number of tumors. Although patients with stage IV tumor had significantly higher CYFRA 21-1 concentrations than those with stages I, II, and III, CYFRA 21-1 was not associated with postoperative prognosis.

CONCLUSIONS

Although high concentrations of CYFRA 21-1 were often detected in patients with a tumor diameter greater than 5 cm or tumor thrombus in the major portal vein, CYFRA 21-1 is not a useful diagnostic tool for hepatocellular carcinoma because of its low sensitivity.

Screening tests for hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is rising throughout the world. HCC meets the criteria for which a disease benefits from screening or surveillance: it is an important health problem; those with cirrhosis are the targets for surveillance; there is acceptable treatment if diagnosed early; surveillance using alpha-fetoprotein and ultrasound has been shown to be cost effective; surveillance is widely implemented by health care professionals and accepted by patients; standardized recall procedures exists; and the screening tests must achieve an acceptable level of accuracy in the population undergoing screening. The latter point is the main limitation of surveillance for HCC. In this review we will discuss the currently available tests for the surveillance of HCC.

From proteomic analysis to clinical significance: overexpression of cytokeratin 19 correlates with hepatocellular carcinoma metastasis

To better understand the mechanism underlying the hepatocellular carcinoma (HCC) metastasis and to search potential markers for HCC prognosis, differential proteomic analysis on two well-established HCC cell strains with high and low metastatic potentials, MHCC97-H and MHCC97-L, was conducted using two-dimensional gel electrophoresis followed by matrix-assisted laser desorption/time-of-flight mass spectrometry. Cytokeratin 19 (CK19) was identified and found to be overexpressed in MHCC97-H as compared with MHCC97-L. This result was further confirmed by two-dimensional Western blot analysis and immunofluorescence assay. Furthermore, one-dimensional Western blot analysis showed consistently increased CK19 expression in progressively more metastatic cells. Immunohistochemical study on 102 human HCC specimens revealed that more patients in the CK19-positive group had overt intrahepatic metastases (satellite nodules, p < 0.05; vascular tumor emboli, p < 0.001; tumor node metastatis staging, p < 0.001). CK19 fragment CYFRA 21-1 levels measured in sera from nude mice model of human HCC metastasis with radioimmunoassay increased in parallel with tumor progression and rose remarkably when pulmonary metastases occurred. The results demonstrated that overexpression of CK19 in HCC cells is related to metastatic behavior. Serum CK19 level might reflect the pathological progression in some HCC and may be a useful marker for predicting tumor metastasis and a therapeutic target for the treatment of HCC patients with metastases.

Screening tests for hepatocellular carcinoma in patients with chronic hepatitis C: a systematic review

This systematic review addresses the following questions: (1) What is the efficacy of using screening tests for hepatocellular carcinoma (HCC) in improving outcomes in chronic hepatitis C, and (2) what are the sensitivity and specificity of screening tests for HCC in chronic hepatitis C? The search strategy involved searching Medline and other electronic databases between January 1985 and March 2002. Additional articles were identified by reviewing pertinent articles and journals and by querying experts. Articles were eligible for review if they reported original human data from studies of screening tests that used virological, histological, pathologic, or clinical outcome measures. Data collection involved paired reviewers who assessed the quality of each study and abstracted data. One nonrandomized prospective cohort study suggested that HCC was detected earlier and was more often resectable in patients who had twice yearly screening with serum alpha-fetoprotein (AFP) and hepatic ultrasound than in patients who had usual care. Twenty-four studies, which included patients with chronic hepatitis C or B or both, addressed the sensitivities and specificities of screening tests. They were relatively consistent in showing that the sensitivity of serum AFP for detecting HCC usually was moderately high at 45% to 100%, with a specificity of 70% to 95%, for a threshold of between 10 and 19 ng/mL. The few studies that evaluated screening with ultrasound reported high specificity, but variable sensitivity. In conclusion, screening of patients with chronic hepatitis C with AFP and ultrasound may improve detection of HCC, but studies are needed to determine whether screening improves clinical outcomes.

Proteomic analysis of cytokeratin isoforms uncovers association with survival in lung adenocarcinoma

Cytokeratins (CK) are intermediate filaments whose expression is often altered in epithelial cancer. Systematic identification of lung adenocarcinoma proteins using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry has uncovered numerous CK isoforms. In this study, 93 lung adenocarcinomas (64 stage I and 29 stage III) and 10 uninvolved lung samples were quantitatively examined for protein expression. Fourteen of 21 isoforms of CK 7, 8, 18, and 19 occurred at significantly higher levels (P < .05) in tumors compared to uninvolved adjacent tissue. Specific isoforms of the four types of CK identified correlated with either clinical outcome or individual clinical-pathological parameters. All five of the CK7 isoforms associated with patient survival represented cleavage products. Two of five CK7 isoforms (nos. 2165 and 2091), one of eight CK8 isoforms (no. 439), and one of three CK19 isoforms (no. 1955) were associated with survival and significantly correlated to their mRNA levels, suggesting that transcription underlies overexpression of these CK isoforms. Our data indicate substantial heterogeneity among CK in lung adenocarcinomas resulting from posttranslational modifications, some of which correlated with patient survival and other clinical parameters. Therefore, specific isoforms of individual CK may have utility as diagnostic or predictive markers in lung adenocarcinomas.