Evidence of tumour microenvironment and stromal cellular components in retinoblastoma

Background: The tumour microenvironment (TME) consisting of tumour cells and multiple stromal cell types regulate tumour growth, invasion and metastasis. While the concept of TME and presence of stromal cellular components is widely established in cancers, its significance in the paediatric intraocular malignancy, retinoblastoma (RB), remains unknown. Methods: The study qualitatively identified the presence of multiple stromal cellular subtypes in RB TME by immunohistochemistry. Results: Results of the study identified the presence of stromal cell types such as endothelial cells, tumour-associated macrophages, fibroblasts, cancer-associated fibroblasts, retinal astrocytes and glia in RB TME. The extent of stromal marker positivity, however, did not correlate with histopathological features of RB. Conclusions: The findings of the study convincingly suggest the presence of a stromal component in RB tumours. The interactions between stromal cells and tumour cells might be of profound importance in RB progression.