Alpha-fetoprotein (AFP)-producing adenocarcinoma from the gastrointestinal tract (APA-GI) is a rare type of highly malignant tumor with a poor prognosis. It may originate from any site along the GI tract with similar clinicopathological characteristics. As limited research had ever described the characteristics of APA-GI, the present article intends to systemically investigate the clinicopathological characteristics of APA-GI from a single center's retrospective study to deepen the understanding of the disease. A total of 177 patients pathologically diagnosed with APA-GI between 2010 and 2017 at the Second Affiliated Hospital of Zhejiang University, School of Medicine, were included. Also, clinical data of 419 gastric cancers and 609 colorectal cancers from The Cancer Genome Atlas database were also extracted. Clinical information of patients from Second Affiliated Hospital of Zhejiang University, School of Medicine, was collected, and a median follow-up of 14.5 months was performed to investigate clinical characteristics of APA-GI. For the pathological characteristics of APA-GI, hematoxylin–eosin sections were reviewed, and immunohistochemistry of AFP was performed. The results showed that the primary tumor could develop through the whole GI tract, including the esophagus (0.6%), stomach (83.1%), duodenum (1.1%), ileum (0.6%), appendix (0.6%), colon (5.1%), and rectum (7.9%). Hepatoid adenocarcinoma is the main pathological feature of APA-GI. AFP expression level in tumor tissue was not strictly associated with serum AFP or hepatoid differentiation. The prognosis of APA-GI was worse than that of common adenocarcinoma of the GI tract and liver metastasis, and high AFP levels suggest poor prognosis in patients with APA-GI. Therefore, the present study was the first research to systemically explore the clinicopathological characteristics of APA-GI. APA-GI occurs through the whole GI tract with a significantly worse prognosis than common adenocarcinoma of GI. APA-GI should be regarded as one kind of disease for its similar clinicopathological characteristics within patients.

No abstract

Alpha-fetoprotein-producing gastric cancer (AFPGC) is a rare but highly malignant subtype of gastric cancer (GC) characterized by elevated serum alpha-fetoprotein (AFP) levels (>20 ng/mL). AFPGC accounts for 1.3%-15% of all GCs. 1 Patients with AFPGC have an aggressive clinical course, early occurrence of multiple organ metastases, primary multidrug resistance, and a poor prognosis. The 5-year survival rate of patients with stage IV AFPGC is 4.4%. 2 The pathogenesis of AFPGC is still not fully understood and effective therapeutic targets are lacking.In recent years, whole-exome sequencing (WES) has been used to study the genetic mutation profiles of AFPGC. In our previous study, we performed whole-exome sequencing of 29 cases of AFP-producing gastrointestinal cancer (AFPGI),