Preliminary study of some of the main intratumor stroma components in gastric carcinomas.

Aim: The relationship between stromal compartment and tumor behavior in gastric carcinomas is still poorly understood and defined. Therefore, the authors started, with this preliminary study, an analysis of stromal compartment morphology and behavior in tumors arising from gastric mucosa epithelium.

Materials and methods: The study group included 75 patients operated for gastric carcinoma. Five parameters describing tumor morphology and behavior and eight parameters describing tumor stroma (TS) morphology were assessed. Histopathological examination included six serial sections of formalin-fixed, paraffin-embedded tumor tissue samples, stained with three classical stains and three antibodies to reveal the different parameters. For data comparison, Pearson's correlation test and the chi-squared (χ²) correlation test were used.

Results: Studied tumors were, usually, infiltrating, undifferentiated∕diffuse type, invasive in subserous spaces and with a Ki67 index higher than 20%. Collagen fibers dominated the stromal components, with a predominance of mature type and an average fibrillary index of 2.7. The whole amount of stromal components accounted for around one quarter of the tumor area. Mature collagen fibers were in opposite correlation with their immature counterpart, and both were in opposite correlation with smooth muscle fibers and expressed an opposite trend of correlation with components of vascular compartment. The whole amount of stromal components had divergent behavior with the components of vascular compartment. The latter expressed generally an opposite trend of correlation with individual fibrillary stromal components. We found only isolated relationships statistically significant between stromal components and tumor characteristics.

Conclusions: TS is in a continuous remodeling process in relation to the evolution of tumor parenchyma, tumors less differentiated proving to have an immature stroma, with newly formed collagen fibers and higher vascular density. Further studies are required.