In breast cancer, vascular endothelial growth factor (VEGF) is a prognostic factor, but the relationship of VEGF mRNA levels with various parameters or tumor progression is unclear. VEGF mRNA levels were measured in 48 cases of invasive ductal carcinoma by using laser capture microdissection and quantitative reverse transcription-polymerase chain reaction (RT-PCR). The mean VEGF mRNA levels were compared among different histological types and grades in 41 and 29 samples of invasive and intraductal components, respectively. VEGF mRNA levels were always higher in cancerous cells than in non-cancerous cells, but mean VEGF mRNA levels were not significantly different between invasive component (3.24 +/- 3.18-fold the value of non-cancerous tissue) and intraductal component (4.14 +/- 4.43-fold). They were higher in papillotubular type than in other types, and higher in grade 2 carcinomas than in grade 3 carcinomas of invasive component, and higher in comedo type than in other types of intraductal component. Mean VEGF mRNA levels were higher in the VEGF-immunopositive group than in the VEGF-immunonegative group. There was no correlation between VEGF mRNA levels and tumor size, nodal status, or hormone receptor status. VEGF expression may play an important role in the development of both invasive and intraductal carcinoma components, especially those carcinoma components of less aggressive histological features.