Sulfite oxidase (SUOX) and glucose transporter 1 (GLUT1) expression both have been shown to be independent prognostic factors in patients with large duct type intrahepatic cholangiocarcinoma (iCCA), with no correlation demonstrated between the 2 biomarkers, according to a new study published in Human Pathology.

A clinicopathologic study was conducted among 96 consecutive patients who had been diagnosed with large duct type iCCA following surgery at Kurume University Hospital in Japan between 2000 and 2018.

The investigators of the present study sought to clarify the relationship between SUOX and GLUT1 expression in patients with large duct type iCCA and the mechanism of mitochondrial energy metabolism among those with the disease. Proportion score was utilized to assess expression of the biomarkers.

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GLUT1, one of the biomarkers of iCCA, is known to be an important factor in energy metabolism, particularly glucose metabolism, which impacts disease prognosis. Glucose is imported into the cytoplasm of the cell via such glucose transporters as GLUT1, and GLUT1 expression is known to be upregulated in many different types of cancer.

SUOX is an enzyme that is present in the mitochondria and converts sulfite to sulfate. SUOX is known to be an important prognostic factor in hepatocellular carcinoma (HCC), as well as in other forms of cancer.

Read more about the prognosis of cholangiocarcinoma

Studies show that iCCA is the second most common primary liver cancer after HCC. Moreover, the incidence of iCCA has been on the rise in many countries, including Japan. iCCA is a malignant disease that carries a poor prognosis, with a 5-year survival rate of 30.9% being reported in 2020, as opposed to a 5-year survival rate of 50.4% in those with HCC.

The current study performed immunohistochemistry analysis on paraffin-embedded surgical sections from the study participants. Of the 96 patients with iCCA, 76.0% demonstrated low SUOX expression and 68.8% showed high GLUT1 expression.

Results of the study showed that the 5-year survival rate of patients with iCCA and low SUOX expression was significantly shorter compared with those with iCCA and high SUOX expression (P =.001). In contrast, the 5-year survival rate among individuals with iCCA and high GLUT1 expression was significantly shorter than that of those with iCCA and low GLUT1 expression (P =.005).

The combination of low SUOX expression and high GLUT1 expression was the most common, which was observed in 53.1% (51 of 96) of patients. Overall survival was significantly shorter in these individuals as well. The researchers concluded that “molecular pathology studies in various carcinomas should be pursued in the future.”


Kinjo Y, Naito Y, Akiba J, et al. SUOX and GLUT1 are biomarkers for the prognosis in large duct type intrahepatic cholangiocarcinoma. Hum Pathol. Published online June 25, 2022. doi:10.1016/j.humpath.2022.06.020