Inter- and intra-tumoral relationships between vasculature characteristics, GLUT1 and budding in colorectal carcinoma.

Vascular characteristics, hypoxia and tumor budding are features that have been implied in the biology and prognosis of colorectal cancer. Internal relationships and the inter- and intra-tumoral variation of these tumor properties remain to be determined. In the current study we have characterized blood vessel status in different areas of CRC and in the peritumoral fibroblastic stroma. Analyses of these characteristics have been supplemented by characterization of budding and hypoxia. Analyses revealed significantly lower values of vessel perimeter (VP) and vessel lumen area (VL) at the invasive front and surrounding stroma as compared to the tumor center. Also, the number of vessels (VN) in the peritumoral stroma was higher than in the center. Thus, tumor center displays larger and fewer vessels as compared to the tumor periphery. GLUT1 expression was correlated directly with VN (r=0.351, p=0.028) and inversely with VL and VP (r=-0.432, p=0.006 and r=-0.484, p=0.002) at the invasive front. Moreover, GLUT1 expression, VP at the invasive front, and VN in the surrounding peritumoral stroma, were associated with budding score (r=0.574, p<0.000, r=-0.340, p=0,034 and r=-0.389, p=0.025 respectively). Furthermore, GLUT1, budding score, vessel number in peritumoral stroma, and vessel size in the invasive front, were significantly different in tumors with or without lymph node metastasis. This study reports previously unrecognized relationships between localization-specific vascular characteristics, hypoxia and tumor budding. The findings suggest potential functional relationships, which should be further explored, and also highlight the inter-tumoral variations in vasculature, which is highly relevant for ongoing efforts to identify vessel-based biomarkers.