(1) Background: Human SERPINB5, commonly known as maspin, has diverse functions as a tumor suppressor. Maspin has a novel role in cell cycle control, and common variants were discovered to be associated with gastric cancer (GC). Maspin was proven to also affect the EMT and angiogenesis of gastric cancer cells via the ITGB1/FAK pathway. Information about the maspin concentrations correlated with different pathological features of the patients may facilitate the fast diagnosis and personalized treatment of patients. The novelty of this study is given by the correlations established for the maspin levels in different biological features and clinicopathological features. These correlations can be extremely useful for surgeons and oncologists. (2) Patients and methods: Patients with clinical and pathological features, given the small number of samples available for this study, were selected from the database of the project GRAPHSENSGASTROINTES, and used in accordance with the Ethics Committee approval nr. 32,647/2018 awarded by the County Emergency Hospital from Targu-Mures. Stochastic microsensors were used as new screening tools for the determination of the concentration of maspin in four types of samples: tumoral tissues, blood, saliva and urine. (3) Results: The results obtained using the stochastic sensors were correlated with those tabulated in the clinical and pathological database. A series of assumptions regarding the values and practice important features for surgeons and pathologists were made. (4) Conclusions: This study provided a few assumptions regarding the correlations between the values of maspin levels in the analyzed samples and the clinical and pathological features. These results may be useful as preoperative investigations in order to help surgeons localize, approximate and choose the best treatment. These correlations may facilitate minim invasive and fast diagnosis of gastric cancer based on reliable detection of maspin concentration in biological samples (tumoral tissues, blood, saliva and urine).