A 42-year-old male presents with 2 months of epigastric dull pain. Gastroscopy reveals a 0.5cm × 0.5cm superficial erosion in the antrum of the stomach. Pathological diagnosis is adenocarcinoma. Surgical exploration shows 2 enlarged lymph nodes along the lesser curvature. Resected specimen pathology indicates tumor involvement of the mucosal and submucosal layers with lymph node metastasis. The diagnosis is: