Liver transplantation and hepatocellular carcinoma 2023: a narrative review of management and outcomes

BACKGROUND AND OBJECTIVE

Hepatocellular carcinoma (HCC) is a leading cause of morbidity and mortality in the United States. For certain patients, liver transplantation (LT) may be curative. The determination of which patients would benefit most from transplant and have the lowest risk of post-transplant recurrence has evolved as technology and treatments have expanded. We aim to review epidemiological changes in the HCC landscape, selection criteria for transplant, organ allocation, bridge therapies and post-transplant recurrence, and identify points for palliative care involvement.

METHODS

Literature review was performed using PubMed MeSH searches in addition to reference list review. Additional information was retrieved from government regulatory and procurement organizations.

KEY CONTENT AND FINDINGS

Metabolic and alcohol-associated liver diseases have surpassed hepatitis C as the leading causes of LT over the last decade, and have also risen as the underlying conditions seen in patients with HCC requiring LT. The United Network for Organ Sharing (UNOS) coordinates organ allocation, which includes disease severity, waitlist time, blood type, and distance from donor hospital. It has progressed to incorporate treatment response and alpha-fetoprotein into its listing criteria for patients with HCC, in addition to the well-established Milan Criteria (MC, one tumor <5 cm, ≤3 tumors ≤3 cm). Therapies to bridge patients until LT include locoregional therapies as well as immunotherapy. Dropout on the waitlist is seen up to 20% either due to decompensation or progression of disease. Recurrence of HCC post-transplant remains challenging. Given this, current guidelines recommend early palliative care involvement regardless of transplant listing status for both symptom management and advance care planning.

CONCLUSIONS

For patients with HCC with favorable tumor biology, LT can be curative. However, given the symptom burden while awaiting LT and the notable number of patients who are unable to receive a transplant, early palliative care is critical in appropriate management of HCC.

Twenty Novel Disease Group-Specific and 12 New Shared Macrophage Pathways in Eight Groups of 34 Diseases Including 24 Inflammatory Organ Diseases and 10 Types of Tumors

The mechanisms underlying pathophysiological regulation of tissue macrophage (Mφ) subsets remain poorly understood. From the expression of 207 Mφ genes comprising 31 markers for 10 subsets, 45 transcription factors (TFs), 56 immunometabolism enzymes, 23 trained immunity (innate immune memory) enzymes, and 52 other genes in microarray data, we made the following findings. (1) When 34 inflammation diseases and tumor types were grouped into eight categories, there was differential expression of the 31 Mφ markers and 45 Mφ TFs, highlighted by 12 shared and 20 group-specific disease pathways. (2) Mφ in lung, liver, spleen, and intestine (LLSI-Mφ) express higher M1 Mφ markers than lean adipose tissue Mφ (ATMφ) physiologically. (3) Pro-adipogenic TFs C/EBPα and PPARγ and proinflammatory adipokine leptin upregulate the expression of M1 Mφ markers. (4) Among 10 immune checkpoint receptors (ICRs), LLSI-Mφ and bone marrow (BM) Mφ express higher levels of CD274 (PDL-1) than ATMφ, presumably to counteract the M1 dominant status via its reverse signaling behavior. (5) Among 24 intercellular communication exosome mediators, LLSI- and BM- Mφ prefer to use RAB27A and STX3 than RAB31 and YKT6, suggesting new inflammatory exosome mediators for propagating inflammation. (6) Mφ in peritoneal tissue and LLSI-Mφ upregulate higher levels of immunometabolism enzymes than does ATMφ. (7) Mφ from peritoneum and LLSI-Mφ upregulate more trained immunity enzyme genes than does ATMφ. Our results suggest that multiple new mechanisms including the cell surface, intracellular immunometabolism, trained immunity, and TFs may be responsible for disease group-specific and shared pathways. Our findings have provided novel insights on the pathophysiological regulation of tissue Mφ, the disease group-specific and shared pathways of Mφ, and novel therapeutic targets for cancers and inflammations.