Figure 8

The correlation between CAIX and HIF-1α expression during human development. In the early stage (5–9 weeks of gestation) diffuse HIF-1α immunoreactivity was seen in the CNS (A), primitive intestine (B), chorionic villi (C) and chondrocytes of the disc (D), mesenchymal cells and chondrocytes of the limb (E), and the skin (E arrow). In contrast, no CAIX expression was seen in the CNS (A), primitive intestine (B), and chorionic villi (C). Co-expression of HIF-1α and CAIX was seen in the skin (E) and the cells involved in chondrogenesis (D, E). During later human development, around 19–20 weeks, HIF-1α expression was persistently observed in the kidney (F) and rectum (G) but no CAIX expressing cells were seen in these organs. However, a degree of overlap between CAIX and HIF-1α expression was seen in the skin (H), squamous mucosa of the vagina and the cervix (I and J). W = gestational age in weeks. Original magnifications: A, B, D-H (40×); C (left panel 20×; right panel 40×); I (20×); J (left panel 20×; right panel 40×).