FOSL1 and benign neoplasm: By contrast, Song et al.[31] found that 90.2% of all breast carcinomas analyzed (n = 445) showed nuclear and cytoplasmic Fra-1 over-expression whereas only 9.2% of the samples (n = 41) showed only nuclear Fra-1 over-expression; of the 20 benign tumors examined, only 3 showed weak cytoplasmic immuno-reactivity that co-existed with the nuclear reactivity that was present in all samples.