Basal cell carcinoma--an in-vivo model of human tumour microcirculation?

The role of angiogenesis in tumour growth and metastasis is well established. However, investigations of tumour microcirculation to date have used either biopsy material from human tumours, or animal models in vivo. We have studied the tumour microcirculation in vivo in human skin cancers using video-microscopy to examine 12 basal cell carcinomas (BCCs) on the head and neck of 11 patients, and compared the vessels with those seen in the peri-lesional skin, and in normal control skin on the opposite side of the body. The vessels seen within the BCCs were markedly abnormal qualitatively, forming bizarre, disorganized patterns. Quantitative analysis revealed that the mean diameter (+/-standard deviation) of the largest vessel was significantly greater within the BCC (0.086+/-0.029 mm) than that in the control skin (0.034+/-0.012 mm) (P<0.001). The area fraction, a measure of the area of tissue occupied by vessels, was increased highly significantly within the BCCs (0.158+/-0.038) compared with both peri-lesional skin (0.029+/-0.012) and control skin (0.027+/-0.010) (P<0.001). Length density, the length of blood vessel per unit area of tissue, was also highly significantly greater within the lesion (210.22+/-66.05 cm(-1)) compared to peri-lesional (27.10+/-15.67 cm(-1)) and control skin (28.27+/-15.81 cm(-1)) (P<0.001). This is the first study to have demonstrated that BCCs possess a distinct tumour microcirculation which can be observed directly, and assessed quantitatively. Prospective studies of tumour progression, possibly after intervention with angiogenesis inhibitors, are possible.