Background: Despite numerous investigations, we still do not have a specific marker for pancreatic ductal adenocarcinoma. Only guideline-recommended biomarker for pancreatic ductal adenocarcinoma is the CA19-9, but it is also present in other gastrointestinal diseases. IMP3 is a new potential biomarker that is over-expressed in some cancers. The aims of our study were (1) to assess IMP3 in benign pancreatic lesions and pancreatic cancer, and (2) to estimate its concentrations in localized and advanced pancreatic cancer.
Patients and methods: Seventy-five patients with solid pancreatic lesions who underwent EUS-FNA were included. Patients were divided into three groups: benign lesions, cancer localized only on the pancreas, and patients with advanced pancreatic cancer (locally advanced or with distal metastases). Immunoreactivity of IMP3 was assessed on cytological smears sampled by endoscopic ultrasound.
Results: IMP3 was expressed in 89% of the patients with pancreatic cancer and not in benign lesions. Stronger expression of IMP3 protein and stage of the pancreatic cancer was statistically significant. IMP3 was expressed in all localized cancers and in 85% of patients with advanced pancreatic cancer. In the subgroup with locally advanced cancer, IMP3 was expressed in 88%, and in 83% of patients in the subgroup with distal metastasis (P = 0.007). In the present study, sensitivity was 89%, specificity 100%, with positive predictive value of 100% and negative predictive value of 63%.
Conclusion: There is a positive correlation between IMP3 expression and TNM stages of the pancreatic cancer. Higher expression of IMP3 on EUS-FNA specimens can suggest poorer prognosis.