Previously, we proposed a new classification of tumor microvessels (MVs) on the basis of their morphological features and clinical significance. The aim of this study was to summarize the obtained results and establish the predictive value of different types of tumor MVs for assessing the risk of metastasis to regional lymph nodes (RLNs) in glandular and squamous cell carcinomas.<i> Materials and methods.</i> A total of 385 archival samples of gastric cancer stages I--III, breast cancer stages I--IIIA, cervical squamous cell carcinoma stages I--IIA, and lung squamous cell carcinoma stages I--IIIA were studied. The tumor sections were processed routinely and subjected to immunohistochemistry with antibodies against cluster of differentiation 34 (CD34) and podoplanin. To assess independent predictors of the risk of metastasis to RLNs, correlation analysis and univariate and multivariate logistic regression analyses were performed. Statistical analysis was performed via Statistica 10.0 software. <i>Results.</i> For patients with gastric cancer and breast cancer, the independent predictors of a high risk of metastasis to RLNs are T2 (p=0.007) and T3 (p<0.00001) stages, tumor grade 3 (p=0.0002), the presence of lymphovascular invasion (LVI) (p=0.044) and peritumoral retraction clefts (p=0.008). For patients with squamous cell carcinoma of the cervix and lung, independent predictors of a high risk of metastasis to RLNs are the T2 (p=0.01) and T3 (p=0.007) stages, the presence of LVI (p=0.0014), dilated capillaries (DCs) of the "contact type" (p=0.0007), capillaries in the tumor solid component (p=0.046) and peritumoral retraction cleftings (p=0.0006). <i>Conclusion</i>. The results of the present study indicate that when assessing the risk of metastasis to RLNs, it is advisable to consider the presence of peritumoral retraction clefting and LVI in both glandular and squamous cell carcinomas. In addition, in squamous cell carcinomas, the accuracy of assessing the risk of metastasis to RLNs can be increased by taking into account "contact-type" DCs and capillaries in the solid component of the tumor.
