Low expression of moonlight gene ALAD is correlated with poor prognosis in hepatocellular carcinoma

Moonlighting genes may involve in the progression of hepatocellular carcinoma (HCC), and the establishment of a prognostic signature based on moonlighting genes may help predict the prognosis of HCC patients.

This study aimed to construct a prognostic signature based on moonlighting genes in HCC and determine whether there is a correlation with tumor microenvironment or immune responses. Then we used HCC cell lines and an HCC cDNA microarray to illuminate the role of moonlighting gene in prognosis of HCC.

We constructed an original prognostic signature based on eight moonlighting genes (ABCB1, S100A9, NCL, PRDX6, ALAD, YBX1, POU2F1, RPL5) with strong prognosis prediction capability. The prognostic signature may demonstrate the immune status of patients with HCC, because high-risk subgroups had significantly higher scores for regulatory T cells, dendritic cells, T follicular helper cells, macrophages, and major histocompatibility complex-I, and different expression levels of immune checkpoint molecules. Importantly, patients in the high-risk subgroup exhibited higher tumor immune dysfunction and exclusion scores, suggesting that they might be less sensitive to immunotherapy. The roles of ABCB1, S100A9, NCL, PRDX6, YBX1, and POU2F1 in HCC have been reported. However, there have been no reports on the association between ALAD and HCC. Then we used bioinformatics to confirm that ALAD expression was lower in HCC and low expression of ALAD was an indicator of poor prognosis. Moreover, we found that ALAD expression was lower in HCC cells than that in normal human hepatocytes or tumor-adjacent tissues, it was negatively correlated with the pathological grade, and low expression of ALAD was related to poor prognosis in patients with HCC.

We have successfully established a novel prognostic signature based on moonlighting genes, with a strong predictive capability for prognosis, immune status, and possible response to immunotherapy. Additionally, we have identified ALAD as a prognostic biomarker for HCC.