Dynamic liver function assessment by the [13C]
methacetin maximal liver function capacity (LiMAx) test reflects the overall hepatic
cytochrome P-450 (
CYP) 1A2 activity. One proven strategy for preoperative risk assessment in liver surgery includes the combined assessment of the dynamic liver function by the LiMAx test, the volumetric analysis of the liver, and calculation of future liver remnant function. This so-called volume-function analysis assumes that the remaining
CYP1A2 activity in any
tumor lesion is zero. The here presented study aims to assess the remaining
CYP1A2 activities in different hepatic
tumor lesions and its consequences for the preoperative volume-function analysis in patients undergoing liver surgery. The
CYP1A2 activity analysis of neoplastic lesions and adjacent nontumor liver tissue from resected
tumor specimens revealed a significantly higher
CYP1A2 activity (median, interquartile range) in nontumor tissues (35.5, 15.9-54.4 µU/mg) compared with
hepatocellular adenomas (7.35, 1.2-32.5 µU/mg),
hepatocellular carcinomas (0.18, 0.0-2.0 µU/mg), or colorectal liver
metastasis (0.17, 0.0-2.1 µU/mg). In nontumor liver tissue, a gradual decline in
CYP1A2 activity with exacerbating
fibrosis was observed. The
CYP1A2 activity differences were also reflected in
CYP1A2 protein signals in the assessed hepatic tissues. Volume-function analysis showed a minimal deviation compared with the current standard calculation for
hepatocellular carcinomas or colorectal liver
metastasis (<1% difference), whereas a difference of 11.9% was observed for
hepatocellular adenomas. These findings are important for a refined preoperative volume-function analysis and improved surgical risk assessment in
hepatocellular adenoma cases with low LiMAx values. NEW & NOTEWORTHY The
cytochrome P-450 (CYP) 1A2-dependent maximal liver function capacity test reflects the overall functional capacity of the liver. To which extent hepatocellular
tumors harbor
CYP1A2 activity and thus contribute to the maximal liver function capacity test outcome is unknown. We here show that
hepatocellular adenomas but not
hepatocellular carcinomas or colorectal liver
metastasis contain significant residual
CYP1A2 activity. These findings are important for an improved preoperative volume-function analysis and an accurate surgical risk assessment in
hepatocellular adenoma cases.