Abstract 4842
Background
The incidence of pancreatic cancer (PAC) has continued to rise in recent years. PAC can be divided into head of PAC (HPAC) and body/tail of PAC (BTPAC) by the anatomical location. The patients (pts) with BTPAC are usually diagnosed at relatively advanced stage and had worse survival than those with HPAC. The comparative molecular signatures between different locations in Chinese PAC pts remain unclear.
Methods
154 tumor specimens (HPAC, N = 85; BTPAC, N = 69) and matched normal blood samples of Chinese PAC pts were detected and analyzed in a CAP&CLIA certified laboratory (OrigiMed company) with Yuansu panel including 450 genes. Total 100 males (65%) and 54 females (35%) with a mean age of 61 years old (yrs) were enrolled. We measured the somatic variations and calculated tumor mutational burden (TMB) after filtering known driver mutations (muts). Meanwhile, germline muts were analyzed among the tumor susceptibility genes. Fisher tests were used for comparative analyses.
Results
The median age in HPAC and BTPAC was 60 yrs and 62 yrs. Pts with stage 3&4 accounted for 40% and 60% in HPAC and BTPAC (P<0.05). Genomic alterations of KRAS and SMAD4 were significantly more prevalent in BTPAC (KRAS in BTPAC vs. HPAC= 97% vs. 82%, P=0.004; SMAD4 in BTPAC vs. HPAC= 42% vs. 21%, P=0.008). 2 NTRK3 fusions (3%) were found in BTPAC but 0 in HPAC. Additionally, muts frequency in Wnt pathway was 57% in BTPAC, whereas 37% in HPAC (P=0.02). No significant difference was found in TP53 (83% vs. 81%), CDKN2A (32% vs. 27%) and germline muts frequency (12% vs. 14%) between BTPAC and HPAC, nor in the mean TMB value (3.22 muts/Mb vs. 3.59 muts/Mb). For HPAC, there were more muts in HR pathway genes (24% vs. 19%), although the difference was not statistical significance. 2 BRCA2 germline muts were found in HPAC but neither BRCA1 nor BRCA2 was found in BTPAC.
Conclusions
Genomic pattern did not show apparent difference between the anatomic locations of PAC. However, we found more driver muts in KRAS and SMAD4 and more Wnt pathway muts related to proliferation and metastasis in BTPAC. Further research should be done to better understand the cancer biology among the locations and identify more therapy targets for precision medicine.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4317 - Prognostic factors analysis of 343 patients with adenocarcinoma of esophagogastric junction
Presenter: Yixun Lu
Session: Poster Display session 2
Resources:
Abstract
4099 - Effects of preoperative preparation time on efficacy of neoadjuvant chemotherapy (SOX) in patients with advanced gastric cancer
Presenter: Xinxin Wang
Session: Poster Display session 2
Resources:
Abstract
3769 - The prognostic value of higher absolute lymphocyte counts for patients with surgically resected non-advanced gastric cancer
Presenter: Se Jun Park
Session: Poster Display session 2
Resources:
Abstract
1718 - Trastuzumab and pertuzumab added to neoadjuvant chemoradiotherapy in resectable HER2+ esophageal adenocarcinoma patients: an update on survival and predictive biomarkers in the TRAP study
Presenter: Charlotte Stroes
Session: Poster Display session 2
Resources:
Abstract
5403 - Interim analysis of a phase II trial of perioperative chemotherapy plus avelumab in esophagogastric and gastric adenocarcinoma
Presenter: Thierry Alcindor
Session: Poster Display session 2
Resources:
Abstract
591 - Evaluation of the introduction of primary G-CSF prophylaxis to the FLOT chemotherapy regimen.
Presenter: Kelly-Marie Crampton
Session: Poster Display session 2
Resources:
Abstract
1402 - Subgroup analyses of a randomized two-by-two factorial phase II trial comparing neoadjuvant chemotherapy with 2 and 4 courses of cisplatin/S-1 (CS) and docetaxel/cisplatin/S-1 (DCS) as neoadjuvant chemotherapy for locally advanced gastric cancer
Presenter: Tsutomu Hayashi
Session: Poster Display session 2
Resources:
Abstract
3743 - HER2 Copy Number as Predictor of Disease-Free Survival in HER2-Positive Resectable Gastric Cancer
Presenter: Zimin Liu
Session: Poster Display session 2
Resources:
Abstract
2032 - Effect of neoadjuvant chemotherapy on the Programmed Death-1 pathway in esophageal and gastric cancer
Presenter: Maria Svensson
Session: Poster Display session 2
Resources:
Abstract
4304 - A user-friendly nomogram to predict relapse-free survival (RFS) in western patients with resected gastric cancer (GC)
Presenter: Massimiliano Salati
Session: Poster Display session 2
Resources:
Abstract