Molecular Alterations Influencing the Prognostic Outcome in Small Pancreatic Cancer (≤2 cm).

PURPOSE: Pancreatic cancer (PC) is the most lethal cancer. The prognosis of small PC (tumor ≤ 20 mm) is better than that of larger PC, indicating the importance of detecting early-stage PC for patient outcome. The aim of this study was to elucidate the molecular features in small PC (≤20 mm).

MATERIALS AND

METHODS

This study included 79 PC tumors (≤20 mm in pathological examination) resected between 2004 and 2022. c-Myc, Caveolin-1, Smad4, and Thrombospondin-1 were examined by immunostaining. These molecular alterations were compared in PC patients with tumor size ≤ 10 mm (n = 11) (14%) and 10 mm < tumor size ≤ 20 mm (n = 68) (86%). Mutation analyses of KRAS, PIK3CA, and BRAF were performed by pyrosequencing in 22 PCs.

RESULTS

PC with 10 mm < tumor size ≤ 20 mm showed significantly worse overall survival and disease-free survival than PC with tumor size < 10 mm (P = 0.024 and P = 0.028). Tumor c-Myc and stromal Caveolin-1 expressions were significantly increased in tumors larger than 10 mm (P = 0.02 and P = 0.04). c-Myc and Caveolin-1 expressions were associated with poor disease-free survival and overall survival. KRAS, PIK3CA, and BRAF mutation status did not differ between the 2 groups.

CONCLUSIONS

Tumor c-Myc and stromal Caveolin-1 overexpressions were detected in tumors larger than 10 mm. Their overexpressions were associated with worse prognosis even in small PC. These molecular alterations in small PC may be a clue for the detection of early-stage PC.