Introduction/Objective: Differently from other digestive malignancies, gastric cancer (GC) pathobiology is still little known and understood. Recently, cytopathology and molecular biology on gastric juice/gastric lavage (GJ/GL) of GC patients have provided novel and interesting results in terms of screening, diagnosis, prognosis, and therapy. However, entertaining cytologic examination and molecular test as a unified solo-run test is previously unreported. Our aim was to assess the new parameter “GL Ca 72.4” for GC patients. Methods: Between April 2012 and July 2013, GJ/GL obtained from 37 surgical GC patients were tested for the presence/absence (GL1/GL0) of exfoliated malignant cells along with the intragastric concentration of Ca 72.4 (normal value <6.49 ng/mL: Ca 72.4n; elevated level ≥6.49 ng/mL: Ca 72.4+). Results: At a median follow-up of 79.3 months, all the GC alive patients were “GL0 Ca 72.4n.” The “GL1 Ca 72.4+” parameter, in comparison with GL0 Ca 72.4n, strongly correlated with deeper tumor invasion (p = 0.027), severe nodal metastasis (p = 0.012), worst metastatic node ratio (p = 0.041), higher number of metastatic lymph nodes (30 vs. 20 nodes, p = 0.014), angiolymphatic invasion (p = 0.044), advanced stage (p = 0.034), and adjuvant therapy (p = 0.044). The Kaplan-Meier model showed that GL1 Ca 72.4+ subjects had shorter overall survival (OS) than GL0 Ca 72.4n cases (9.7 vs. 43.2 months, respectively, p = 0.042). At univariate analysis, the GL1 Ca 72.4+ parameter resulted a significant prognostic factor for OS (p = 0.023). Conclusions: The combined cyto-molecular parameter “GL1 Ca 72.4+” appears to be a strong indicator of aggressive tumor behavior and a significant prognostic factor of poor survival for GC patients.