Figure 5.

Categories of lung metastases according to sizes and numbers of tumors. (A) no metastases (B) +, multiple (>10) small (indicated by arrowheads) and 1–3 medium sized (3–4 mm) metastases; (C) ++, multiple small and more than 3 medium sized metastases and/or 1–3 large (4–5 mm) isolated metastases; (D) +++, lungs overgrown with medium to large metastases growing together, frequently more than 50% of lungs formed by tumor tissue; (E) in some chicks metastases seized the majority of the lungs. Scale bar 1 cm.