According to the World Health Organization (WHO), cancer is one of the leading causes of morbidity and mortality in the world [1]. The most common cases of the disease are breast, lung and colorectal cancer [1]. The therapeutic procedures used for the treatment of cancer are very aggressive, especially chemotherapy, since the drug indiscriminately penetrates and attacks the cellular microenvironment of the whole organism [2]. In this research, mathematical modeling was developed to study the transport of drug nanoparticles in the microenvironment to assess the process of cellular selectivity in the tumor region. Computational models of tumor micromorphology were developed. The biophysical and biochemical conditions of the microenvironment and nanoparticles were implemented. The results showed the interaction of several nanoparticles with diseased cell glands. The remaining particles were displaced by interstitial flow towards the depth of the tumor. In the innermost area of the carcinoma, there is high proliferation of the disease, favoring the selectivity process of the nanoparticles with the malignant glands. This research allows for greater understanding of the dynamics between drug nanoparticles and tumor cells to assess therapeutic effectiveness against cancer.