Association of Mutant KRAS Alleles With Morphology and Clinical Outcomes in Pancreatic Ductal Adenocarcinoma

Prognostic Properties of KRAS Gene Mutation Subtypes in Resected Pancreatic Ductal Adenocarcinoma

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) has a distinct genomic profile, with somatic KRAS mutations occurring in 85%-95% of all PDAC cases. This study aimed to measure the prognostic impact of specific KRAS mutations in resected PDAC patients from a large, high-volume center.

METHODS

This retrospective study included a cohort of PDAC patients who underwent curative-intent pancreatic resection at our institution between 2016 and 2021. Demographic, histologic, and oncologic outcome data were recorded. KRAS status was assessed via next-generation sequencing. Thirty-six (12.8%) wtKRAS, 109 (38.8%) G12D, 76 (27.0%) G12V, 36 (12.8%) G12R, 11 (3.9%) Q61H.

RESULTS

A total of 281 patients were included with wtKRAS (12.8%), G12D (38.8%), G12V (27.0%), G12R (12.8%), accounting for over 90% of the KRAS genotypes. Kaplan-Meier analysis revealed wild-type KRAS to be associated with improved overall survival (68.5±0 vs. 32.1±2.3 mo, P=0.005), and disease-free survival (35.4±0 vs. 20.3±3.9 mo, P=0.043). Cox regression analysis demonstrated worse overall survival with increased age (HR=1.04/y, P<0.01), neoadjuvant chemotherapy (HR=2.01, P<0.01), the presence of lymphovascular invasion (HR=2.47, P<0.01), G12D or G12V KRAS subtypes (P≤0.05), and lack of adjuvant chemotherapy (HR=0.6, P=0.02).

CONCLUSIONS

Next-generation sequencing of the KRAS subtype in resectable PDAC tumors shows that the KRAS G12D/G12V subtypes confer a worse prognosis compared with wild-type KRAS tumors.

The Clinical Implications of KRAS Mutations and Variant Allele Frequencies in Pancreatic Ductal Adenocarcinoma

The KRAS proto-oncogene is a major driver of pancreatic tumorigenesis and is nearly ubiquitously mutated in pancreatic ductal adenocarcinoma (PDAC). KRAS point mutations are detected in over 90% of PDAC cases, and these mutations have been shown to be associated with worse therapy response and overall survival. Pathogenic KRAS mutations are mostly limited to codons 12, 13 and 61, with G12D, G12V, G12R, Q61H, and G13D accounting for approximately 95% of the mutant cases. Emerging data have shown the importance of specific mutant subtypes, as well as KRAS variant allele frequency on clinical prognosis. Furthermore, novel technologies and therapies are being developed to target specific mutant subtypes, with encouraging early results. In this paper, we aim to review the recent studies regarding the relative impact of specific mutant KRAS subtypes on oncologic outcomes, the application of variant allele frequency in next generation sequencing analyses, and the ongoing research into therapies targeting specific mutant KRAS subtypes.