e16000 Background: Gastric cancer with elevated alpha-fetoprotein (AFP) is a special type of gastric cancer with elevated serum AFP. It is often misdiagnosed as primary hepatic cancer due to abnormal AFP and liver metastasis. The AFP level is related to the prognosis of these patients in whom there is prone to high HER2 positive rate. Therefore, anti-HER2 treatment is optional, as well as the emerging immunotherapy with immune checkpoint inhibitors. Methods: Gastric cancer patients with HER2 and serum AFP examination were collected in our hospital from May 2017 till now. Serum AFP level over 7 ng/ml was defined as elevated AFP. The clinical characteristics, treatments and survival of the patients with HER2 positive and elevated AFP were picked and analyzed. Results: Among 135 gastric cancer patients with elevated AFP, 16 (11.9%) were HER-2 positive (12 with HER2 3+, 3 with HER2 2+/FISH+ and 1 with HER2 gene amplification in NGS). The mean serum AFP is 201.4± 476.7ng/ml (range: 7.74 -1335). There were 9 males and 7 females. The mean age was 55 years (range: 38-90). The tumors were located in stomach cardia and fundus in 5 cases, body in 5 cases, antrum in 4 cases, body and antrum in 1 case and whole stomach in 1 case. There were 2 patients in stage III and 14 patients in stage IV with metastasis to lymph node metastasis in 15, liver in 9, abdominal cavity in 3 and peritoneum in 3. As for the treatments, three patients underwent surgery, one of whom with exploratory laparotomy (no antitumor treatment after surgery, died from infection). In 13 advanced patients, 12 patients received systemic antitumor therapies (8 with chemotherapy+Trastuzumab+ immunotherapy, 2 with chemotherapy+Trastuzumab, 1 with chemotherapy+ immunotherapy and 1 with chemotherapy). The chemotherapy regimens were XELOX in 5 cases, SOX in 4 cases and FLOT in 2 cases. The response rate was 50% (6 in 12 patients) and the disease control rate was 100%. The median PFS was 7.5 months in first line therapy with six patients without progression disease yet. The longest PFS with PR lasted for 16.5 months with chemotherapy, trastuzumab and immune checkpoint inhibitor. Conclusions: Gastric cancer with HER2 positive and elevated serum AFP is a disease with special clinical characteristics. Patients with advanced diseases can be treated with chemotherapy, trastuzumab +/- immune checkpoint inhibitors. This combination is expected to become a new regimen to improve survival of such special patients.
NF1-mutated melanomas reveal distinct clinical characteristics depending on tumour origin and respond favourably to immune checkpoint inhibitors
