The number of lung metastasis in different size ranges for pfp / rag2 mice (A) and rag2 mice (B). The metastases size ranges are scaled logarithmically. Three different growth rates were applied on the lung metastases: 1/3 (left), 1/2 (middle) and same (right) growth rate as the primary tumor. According to the observed morphology, metastases in the rag2 mouse stain (B) remain dormant for at least 30 days, before they are able to successfully proliferate. In pfp/rag2 mouse strain (A) metastases are able to successfully proliferate much easier. However they undergo a late dormancy, once they already proliferated a few times and reached a size between 10 and 100 cells.