These latter studies have direct relevance to the significance of N-myc oncogene amplification in neuroblastoma during progression and CD44 gene plasticity of expression in fibrosarcoma during metastasis.
These studies demonstrate (a) opposing selective pressures on CD44s over-expression for s.c. tumor growth and for metastatic spread to the lung and (b) further credence for the significance of CD44 for metastatic spread of fibrosarcomas.