The Clinicopathological Characteristics of Alpha-Fetoprotein-Producing Adenocarcinoma of the Gastrointestinal Tract-A Single-Center Retrospective Study

Abstract

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.

Keywords: AFP-producing; adenocarcinoma; clinical characteristic; gastrointestinal; pathological characteristic.

Figure 1

Characteristics of AFP-GI under a light microscope. (a) Classic primary hepatic carcinoma (100×); (b) Classic hepatoid adenocarcinoma (100×); (c) 1. Zone of adenocarcinoma with moderately differentiation; 2. Zone of adenocarcinoma with hepatoid differentiation (40×); (d) Zone of adenocarcinoma with hepatoid differentiation is composed of cells with round nuclei, coarse chromatin, obvious nucleoli, and clear cytoplasm (400×).

Figure 2

Kaplan–Meier curve between APA-GI and CA-GI. (A–C) Survival differences between APA-GC and CA-GC; (D–F) survival differences between APA-CRC and CA-CRC; (G–I) survival differences between APA-GI and CA-GI; Column 1 shows survival comparison between stages I–III patients. Column 2 shows survival comparison between stage IV patients. Column 3 shows survival comparison between stages I–IV patients. APA-GI patients were composed of 154 APA-GC and APA-CRC from the SAHZU database, whereas CA-GI patients were all extracted from TCGA database. Notably, two APA-GC patients were unable to perform accurate staging due to the lack of medical imaging data. Therefore, they can only be classified as stages I–IV.

Figure 3

Kaplan–Meier curve of APA-GI compared by AFP level. Comparison of survival between APA-GI patients with AFP ≥ 200 ng/ml and AFP <200 ng/ml: (A) compare between stages I–III patients; (B) compare between stage IV patients; (C) compare between stages I–IV patients. Notably, two patients were unable to perform accurate staging due to the lack of medical imaging data. Therefore, they can only be classified as stages I–IV. IRS 0–1, 2–3, 4–8, and 9–12 was referred to negative, week positive, moderate positive and strong positive, respectively.