Microvascular density in non-Hodgkin B-cell lymphomas measured using digital morphometry

Introduction: The growth of solid tumors requires the development of microvessels, therefore tumor expansion depends on angiogenesis. Microvessels provide nutrients and oxygen and remove catabolytic substances, while endothelial cells produce growth factors for tumor cells in a paracrine fashion. The microvascular component of a tumor also plays a role in the metastatic capacity of the tumor, enabling the tumor cells to spread to distant locations by providing a large endothelial surface. Aim: The purpose of this study was to review the literature about angiogenesis regarding malignant lymphomas and to perform basic measurements by means of digital morphometric methods in large B-cell lymphomas and follicular lymphomas. Materials and Methods: After thorough analyzing currently available assessment methods, we performed angiogenesis assessment on 19 randomly selected cases, from paraffin-embedded specimens using digital morphometry. We used immunohistochemistry and the CD34 antigen to mark microvessels. We measured average vascular diameter and a previously successfully applied digital morphometric method to quantify the extent of endothelial area. Results: According to literature data, our knowledge and understanding of angiogenesis grew rapidly from early studies such as Folkman's classic paper. Many studies showed that angiogenesis plays a key role in the biology of tumors and therefore the study of angiogenesis might open new therapeutic possibilities. There have been many studies of angiogenesis in malignant lymphomas, however not as many articles as in other tumor types. Our morphometric studies showed there are statistically significant differences between diffuse large cell lymphoma (DLBCL) and follicular lymphoma (FL) regarding average vascular diameter and that high grade lymphomas tend to have a greater CD34+ endothelial area.