NK cells adjuvant therapy shows survival benefits in a gastric mixed signet ring cell carcinoma patient: A case report

RATIONALE: Advanced signet ring cell (SRC) carcinoma has a worse prognosis. Therefore, early diagnosis and prevention is particularly important; SRC tumors have lower R0 resection rate and are thought to be less chemosensitive than non-SRCC. Consequently, a novel postoperative adjuvant treatment is urgently needed to improve clinical outcomes. PATIENT CONCERNS: A 41-year-old female with advanced gastric SRC carcinoma was treated with radical gastrectomy and oxaliplatin-based regimen for 6 cycles after surgery. She was suspected of recurrence with the high level of carbohydrate antigen (CA) 72-4. DIAGNOSES: The gastroscopy revealed SRC carcinoma of gastric antrum and poorly differentiated adenocarcinoma in some areas. The diagnosis of postoperative pathology report was gastric cancer with stage III C (T4a, N3a, M0). INTERVENTIONS: The level of CA72-4 rapidly increased during the 2 follow-up after the completion of conventional treatment, ex vivo-cultured allogeneic natural killer (NK) cell infusion was offered to prevent recurrence. OUTCOMES: Intravenous injections of NK cells combination with surgical treatment and chemotherapy showed therapeutic effects in this patient with possible relapse. The patient remained disease-free 46 months after the infusion of NK cells until the latest follow-up. LESSONS: CA72-4 appeared to be the most sensitive and specific marker in the gastric cancer patient, and the high level of CA72-4 may indicate the risk of recurrence. This case report provide rationale for NK cell infusion following the rapid increase of CA72-4 to prevent recurrence.