Association of apolipoprotein A2 isoform index with demographic, behavioral, and clinical risk factors for pancreatic ductal adenocarcinoma in a single-center observational study: considerations for development of a pancreatic cancer screening algorithm?

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is associated with high mortality rates therefore early diagnosis and treatment is essential in reducing mortality. Blood tests that can identify high-risk individuals is an unmet medical need. In this pilot observational study, remnant samples from routine clinical lab orders were tested on 265 patients presenting with abdominal pain and/or presence of pancreatitis, pancreatic cyst, gall stones, abdominal infections (due to herpes or H. pylori), hepatic cirrhosis/hepatitis, non-pancreatic cancer, or pre-, new onset, controlled and uncontrolled diabetes.

METHODS

The serum apolipoprotein A2 isoform index, a novel tumor marker, and carbohydrate antigen (CA) 19-9 were correlated to 3 demographic, 4 behavioral and 7 clinical risk factors associated with PDAC and subclassifications therein. In a univariate logistic regression analysis using the tumor markers as a dichotomous variables against the biomarker's respective cutoff concentration, alcohol, smoking, opioid use, pancreatitis, abdominal infections, pancreatic cyst and hepatic cirrhosis/hepatitis were associated with an abnormal apoA2 isoform index.

RESULTS

In a multivariate analysis, alcohol use, smoking, pancreatitis and pancreatitic cyst remain significant. CA19-9 was associated with cirrhosis/hepatitis alone. When categorizing marker data using pre-established cutoffs, patients with abnormal apoA2 index had 4.4 risk factors vs. 3.2 with normal apoA2 isoform index (p < 0.0001). No difference between normal and abnormal results were observed for CA19-9.

CONCLUSIONS

Correlating known PDAC risk factors, apoA2 isoform index and CA19-9 were associated with different factors, suggesting they provide independent information on risk. This may justify the apoA2 isoform index as part of an algorithm with CA19-9 for cancer screening, particularly for high-risk individuals (e.g., genetic risk).