Yuki Adachi (Tokyo / JP; Asahikawa / JP), Rei Noguchi (Tokyo / JP), Julia Osaki (Tokyo / JP), Shuhei Iwata (Tokyo / JP), Yomogi Shiota (Tokyo / JP), Mishie Tanino (Tokyo / JP), Kazuki Sasaki (Tokyo / JP), Sumio Ohtsuki (Kumamoto / JP), Hideki Yokoo (Asahikawa / JP), Tadashi Kondo (Tokyo / JP)
Background: The molecular mechanism by which hepatocellular carcinoma (HCC) relapses after surgery is not well understood. Advances in mass spectrometry and data analysis techniques have enabled accurate and detailed proteomic analysis of formalin-fixed paraffin-embedded (FFPE) samples. This study aims to elucidate the molecular mechanisms behind postoperative recurrence in HCC and identify novel prognostic biomarkers through proteomic analysis of FFPE samples.
Methods: We selected 43 cases with early recurrence (within one year) and 62 cases with no recurrence for over five years from 487 HCC patients who underwent initial curative hepatectomy between 2010 and 2022 in Asahikawa Medical University Hospital. Proteins were extracted from cancerous and non-cancerous areas of thin-sectioned FFPE samples using macro-dissection and ultrasonic treatment with Adaptive Focused Acoustics (AFA) technology to maximize extraction efficiency. Comprehensive proteomic analysis was performed using mass spectrometry after peptide digestion of the extracted proteins.
Results: Approximately 8000 proteins were commonly identified in a quantitative way from all samples. Principal component analysis showed no obvious differences in protein profiles of non-cancerous areas between early recurrence and no recurrence groups, but proteomic differences were observed in cancerous areas of the patients with different prognoses. Notably, hundreds of differentially expressed proteins between the groups were detected in cancerous areas. Enrichment analysis revealed significant upregulation of multiple molecular pathways related to cell proliferation, such as DNA replication, cell cycle, and mismatch repair, in the early recurrence group, identifying several candidate biomarkers.
Discussion: Several proteins and molecular pathways associated with postoperative recurrence of HCC were identified. These observations were consistent with previously reported cancer progression mechanisms, indicating the validity of our results. However, the complexity of recurrence mechanisms also highlights the limitations of predicting prognosis based on single biomarker changes. The development of a prognostic model integrating multiple biomarkers is currently underway.
Conclusion: Proteomic analysis of FFPE samples identified protein groups involved in postoperative recurrence of HCC. However, developing precise prognostic biomarkers and novel therapeutic strategies requires a more comprehensive and detailed analysis approach that considers the interactions of multiple proteins and pathways.