Hepatocellular carcinoma (HCC) is a major health concern worldwide, and its incidence is increasing steadily. Recently, the MAPK/ERK signaling pathway in HCC has gained renewed attention from basic and clinical researchers. The MAPK/ERK signaling pathway is activated in more than 50% of human HCC cases; however, activating mutations in RAS and RAF genes are rarely found in HCC, which are major genetic events leading to the activation of the MAPK/ERK signaling pathway in other cancers. This suggests that there is an alternative mechanism behind the activation of the signaling pathway in HCC. Here, we will review recent advances in understanding the cellular and molecular mechanisms involved in the activation of the MAPK/ERK signaling pathway and discuss potential therapeutic strategies targeting the signaling pathway in the context of HCC.

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MAPK/ERK Signaling Pathway in Hepatocellular Carcinoma

Background: Atezolizumab plus bevacizumab was approved for patients with hepatocellular carcinoma (HCC). Although clinical trials have revealed its efficacy, the outcomes in the real-world clinical practice are unclear. We retrospectively evaluated the efficacy and safety of atezolizumab plus bevacizumab for HCC. Materials and Methods: This is a multicenter study conducted between November 2020 and March 2021. Among the 61 patients, 51 were assessed for progression-free survival (PFS), therapeutic response, and adverse events (AEs). Results: The median PFS was 5.4 months. The objective response rate (ORR) was 35.3%. The disease control rate (DCR) was 86.3%. The incidence rates of AEs at any grade and grade >3 were 98.0% and 29.4%, respectively. The most frequent AE at any grade and grade >3 was hepatic disorder. In patients with a previous history of molecular targeted agent (MTA) or the degree of albumin-bilirubin (ALBI) grade, there were no significant differences in the PFS, ORR, DCR, and incidence rates of AEs. Conclusion: The study demonstrated that atezolizumab plus bevacizumab was effective and safe for patients with HCC even in the real-world setting including patients with a previous MTA history or other than ALBI grade 1.

https://www.mdpi.com/2072-6694/13/11/2786/pdf

Initial Experience of Atezolizumab Plus Bevacizumab for Unresectable Hepatocellular Carcinoma in Real-World Clinical Practice.

The aim of this study was to investigate the early tumor response and safety of atezolizumab plus bevacizumab for patients with unresectable hepatocellular carcinoma in real-world practice. Forty patients with Child-Pugh class A liver function and eastern cooperative oncology group performance status 0 or 1 were enrolled. The objective response rate (ORR) at six weeks after the start of treatment, changes in α-fetoprotein (AFP) and des-γ-carboxyprothrombin, incidence of adverse events (AEs), and changes in albumin-bilirubin (ALBI) score and serum ammonia level, were evaluated. Among 40 patients, 24 had histories of prior molecular targeted agents (MTAs). The ORR was 22.5% based on mRECIST. Multivariate analysis showed that an AFP ratio <1.0 at three weeks (odds ratio 39.2, 95% confidence interval CI 2.37-649.0, p = 0.0103) was the only significant factor for predicting early response. There was no significant difference in the frequency of AEs between patients receiving first-line treatments and others. Fatigue, proteinuria, and ascites were more frequent in patients who experienced prior treatment. No decrease in ALBI score or increase in serum ammonia level was observed. Our study demonstrated that AFP may be useful in assessing early response and that this treatment is safe, including in patients with prior MTA treatments.

Early Tumor Response and Safety of Atezolizumab Plus Bevacizumab for Patients with Unresectable Hepatocellular Carcinoma in Real-World Practice.

Immunotherapeutic treatments in hepatocellular carcinoma; achievements, challenges and future prospects.

A 74-year-old man was diagnosed with hepatocellular carcinoma. The tumor in the liver showed a complete response after transcatheter arterial chemoembolization, but lung, bone, and lymph node metastases were observed, so treatment with atezolizumab plus bevacizumab was initiated. After administration, the scans showed tumor growth, but after continuous administration of atezolizumab plus bevacizumab, the tumors finally reduced in size and showed a partial response. The transient growth of the tumors was considered to be pseudoprogression. Herein, we report a case of pseudoprogression in hepatocellular carcinoma treated with atezolizumab plus bevacizumab.

https://journals.sagepub.com/doi/pdf/10.1177/23247096211058489

A Case of Pseudoprogression in Hepatocellular Carcinoma Treated With Atezolizumab Plus Bevacizumab.

Hepatocellular carcinoma (HCC) is a common cancer globally and a leading cause of cancer-related deaths. Although early-stage disease may be curable by resection, liver transplantation or ablation, many patients present with unresectable disease and have a poor prognosis. Combination treatment with atezolizumab (targeting PD-L1) and bevacizumab (targeting VEGF) in the recent IMbrave150 study was shown to be effective with an acceptable safety profile in patients with unresectable HCC. Herein, we discuss this novel combination in the context of the liver immune environment, summarize the mechanism and pharmacokinetics of atezolizumab and bevacizumab, and examine recent data on other immune checkpoint inhibitor combination strategies as well as future directions in the treatment of patients with advanced HCC.

Xiufeng Liu

Papers

Atezolizumab and bevacizumab for hepatocellular carcinoma: mechanism, pharmacokinetics and future treatment strategies.