Lu, Shelly C.

Abstract Background and Aims: For hepatocellular carcinoma (HCC) with vascular invasion, systemic treatment is recommended but transarterial radioembolization (TARE) is often used in clinical practice. The aim of this study was to investigate the current usage of TARE vs. systemic therapy as a first-line treatment for HCC with vascular invasion in the United States (US). Method: We performed a retrospective cohort study using the National Cancer Database (NCDB), which represents more than 70 percent of newly diagnosed cancer cases nationwide. All HCC patients diagnosed between 2010 and 2015 with the tumor stage of T3BN0M0 according to the 7th edition of the American Joint Committee on Cancer TNM staging system (tumor involving a major branch of a large vein of the liver without lymph nodes or extrahepatic metastasis) and received TARE or systemic treatment as a first-line treatment were included. Multivariable logistic regression was used to estimate factors associated with the utilization of TARE vs. systemic therapy. Results: A total of 1979 patients who received systemic treatment and 524 patients who received TARE were included. The proportion of patients receiving TARE increased from 15.7% in 2010 to 31.4% in 2015 (P<0.01). The median tumor size of the largest lesion was comparable (7.0cm for TARE vs. 7.1 cm for systemic treatment, P=0.43). Factors independently associated with increased likelihood of receiving TARE over systemic treatment were: advanced age (Odds Ratio [OR]: 1.02, 95% confidence interval [CI]: 1.01 - 1.03, p=0.005), insurance status: private (OR: 3.06, 95% CI: 1.61 - 5.65, p<0.001), Medicaid/Medicare (OR: 2.91, 95% CI: 1.52 - 5.31, p<0.001), others (OR: 4.85, 95% CI: 1.90 - 11.62, p<0.001) vs. no insurance, and receiving care in the Midwest vs. Northeast region of the US (OR: 1.89, 95% CI: 1.38 - 2.53, p<0.001). Patients were significantly less likely to receive TARE if receiving treatment at community cancer program (OR: 0.24, 95% CI: 0.098 - 0.49, p<0.001) or comprehensive community cancer program (OR: 0.62, 95% CI: 0.48 - 0.82, p<0.001) vs. academic cancer program. Larger tumor size (OR per 1cm: 0.97, 95% CI: 0.95 - 1.00, p=0.03) and higher Charlson comorbidity index of ≥3 vs. 0 (OR: 0.53, 95% CI: 0.38 - 0.73, p<0.001) were inversely associated with receiving TARE. Recent HCC diagnosis year was associated with an increased likelihood of receiving TARE (OR: 1.23, 95% CI:1.16 - 1.32, p<0.001). Conclusion: The proportion of patients receiving TARE as a first-line treatment for HCC with macrovascular invasion has been increasing in the US. Age, comorbidities, insurance status, tumor size, and the type and location of cancer centers are associated with the usage of TARE vs. systemic treatment in HCC patients with vascular invasion. Citation Format: Joseph C. Ahn, Michael Luu, Walid Ayoub, Alexander Kuo, Andrew Hendifar, Jun Gong, Kambiz Kosari, Shelly Lu, Nicholas Nissen, Ju Dong Yang. Transarterial radioembolization versus systemic treatment for the management of hepatocellular carcinoma with vascular invasion: Analysis of the US National Cancer Database [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2350.

Hepatocellular carcinoma (HCC) is among the leading causes of worldwide cancer‐related morbidity and mortality. Poor prognosis of HCC is attributed primarily to tumor presentation at an advanced stage when there is no effective treatment to achieve the long term survival of patients. Currently available tests such as alpha‐fetoprotein have limited accuracy as a diagnostic or prognostic biomarker for HCC. Liver biopsy provides tissue that can reveal tumor biology but it is not used routinely due to its invasiveness and risk of tumor seeding, especially in early‐stage patients. Liver biopsy is also limited in revealing comprehensive tumor biology due to intratumoral heterogeneity. There is a clear need for new biomarkers to improve HCC detection, prognostication, prediction of treatment response, and disease monitoring with treatment. Liquid biopsy could be an effective method of early detection and management of HCC. Circulating tumor cells (CTCs) are cancer cells in circulation derived from the original tumor or metastatic foci, and their measurement by liquid biopsy represents a great potential in facilitating the implementation of precision medicine in patients with HCC. CTCs can be detected by a simple peripheral blood draw and potentially show global features of tumor characteristics. Various CTC detection platforms using immunoaffinity and biophysical properties have been developed to identify and capture CTCs with high efficiency. Quantitative abundance of CTCs, as well as biological characteristics and genomic heterogeneity among the CTCs, can predict disease prognosis and response to therapy in patients with HCC. This review article will discuss the currently available technologies for CTC detection and isolation, their utility in the clinical management of HCC patients, their limitations, and future directions of research.

Prohibitin 1 (PHB1) is best known as a mitochondrial chaperone, and its role in cancer is conflicting. Mice lacking methionine adenosyltransferase α1 (MATα1) have lower PHB1 expression, and we reported that c‐MYC interacts directly with both proteins. Furthermore, c‐MYC and MATα1 exert opposing effects on liver cancer growth, prompting us to examine the interplay between PHB1, MATα1, and c‐MYC and PHB1's role in liver tumorigenesis. We found that PHB1 is highly expressed in normal hepatocytes and bile duct epithelial cells and down‐regulated in most human hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). In HCC and CCA cells, PHB1 expression correlates inversely with growth. PHB1 and MAT1A positively regulate each other's expression, whereas PHB1 negatively regulates the expression of c‐MYC, MAFG, and c‐MAF. Both PHB1 and MATα1 heterodimerize with MAX, bind to the E‐box element, and repress E‐box promoter activity. PHB1 promoter contains a repressive E‐box element and is occupied mainly by MAX, MNT, and MATα1 in nonmalignant cholangiocytes and noncancerous tissues that switched to c‐MYC, c‐MAF, and MAFG in cancer cells and human HCC/CCA. All 8‐month‐old liver‐specific Phb1 knockout mice developed HCC, and one developed CCA. Five‐month‐old Phb1 heterozygotes, but not Phb1 flox mice, developed aberrant bile duct proliferation; and one developed CCA 3.5 months after left and median bile duct ligation. Phb1 heterozygotes had a more profound fall in the expression of glutathione synthetic enzymes and higher hepatic oxidative stress following left and median bile duct ligation. Conclusion: We have identified that PHB1, down‐regulated in most human HCC and CCA, heterodimerizes with MAX to repress the E‐box and positively regulates MAT1A while suppressing c‐MYC, MAFG, and c‐MAF expression; in mice, reduced PHB1 expression predisposes to the development of cholestasis‐induced CCA. (Hepatology 2017;65:1249‐1266).

c‐Myc induction drives cholestatic liver injury and cholangiocarcinoma (CCA) in mice, and induction of Maf proteins (MafG and c‐Maf) contributes to cholestatic liver injury, whereas S‐adenosylmethionine (SAMe) administration is protective. Here, we determined whether there is interplay between c‐Myc, Maf proteins, and methionine adenosyltransferase α1 (MATα1), which is responsible for SAMe biosynthesis in the liver. We used bile duct ligation (BDL) and lithocholic acid (LCA) treatment in mice as chronic cholestasis models, a murine CCA model, human CCA cell lines KMCH and Huh‐28, human liver cancer HepG2, and human CCA specimens to study gene and protein expression, protein‐protein interactions, molecular mechanisms, and functional outcomes. We found that c‐Myc, MATα1 (encoded by MAT1A), MafG, and c‐Maf interact with one another directly. MAT1A expression fell in hepatocytes and bile duct epithelial cells during chronic cholestasis and in murine and human CCA. The opposite occurred with c‐Myc, MafG, and c‐Maf expression. MATα1 interacts mainly with Mnt in normal liver, but this switches to c‐Maf, MafG, and c‐Myc in cholestatic livers and CCA. Promoter regions of these genes have E‐boxes that are bound by MATα1 and Mnt in normal liver and benign bile duct epithelial cells that switched to c‐Myc, c‐Maf, and MafG in cholestasis and CCA cells. E‐box positively regulates c‐Myc, MafG, and c‐Maf, but it negatively regulates MAT1A. MATα1 represses, whereas c‐Myc, MafG, and c‐Maf enhance, E‐box‐driven promoter activity. Knocking down MAT1A or overexpressing MafG or c‐Maf enhanced CCA growth and invasion in vivo. Conclusion: There is a novel interplay between MATα1, c‐Myc, and Maf proteins, and their deregulation during chronic cholestasis may facilitate CCA oncogenesis. (Hepatology 2016;64:439‐455)