Procalcitonin a novel tumour biomarker for diagnosis, disease monitoring in FLC

A recent study has found procalcitonin to be a sensitive and specific serum biomarker for fibrolamellar carcinoma (FLC), making it a potential target for diagnosis and monitoring of treatment response.

The authors measured serum procalcitonin levels in 34 samples from 18 patients with FLC and in 64 patients with hepatocellular carcinoma (HCC), 24 with cholangiocarcinoma (CCA), and 20 with cirrhosis. They also analysed the expression of CALCA, which encodes procalcitonin, in 27 FLC tumours, 331 HCC tumours, 39 CCA tumours, 71 hepatoblastomas, 34 hepatocellular adenomas, and 55 nontumour liver samples using RNA sequencing.

Additionally, spatial transcriptomics was conducted on three FLC tumours, while procalcitonin immunohistochemistry was performed on 13 FLC tumours and 34 primary or secondary liver cancers.

Eight patients with FLC from the European cohort had a significantly elevated serum procalcitonin (55.2 μg/L) than those with HCC (0.14 μg/L), CCA (0.16 μg/L), and cirrhosis (0.11 μg/L; p=0.0005).

“These findings were validated in a US cohort of 10 patients with FLC compared to HCC and CCA (p=0.0002),” the authors said.

Elevated serum procalcitonin was noted in 83 percent of patients with FLC compared with 3 percent of those with HCC and CCA (p<0.0001). In four patients, changes in serum procalcitonin levels appeared to contribute to radiologic response according to RECIST 1.1.

Furthermore, RNA sequencing showed significant overexpression of CALCA in FLC relative to other primary liver tumours (p<0.0001), as well as spatial transcriptomics localized CALCA expression specifically to tumour cells.

The overexpression of procalcitonin was confirmed by immunohistochemistry in 77 percent of FLC tumours but not in other liver cancers.

“FLC is a rare primary liver cancer that predominantly affects young patients with normal known serum tumour biomarkers,” the authors said.