TNF and cancer: We explored expression of miR-21 and TNF-α mRNA at the invasive front of four colon cancers in order to elucidate expression interplay between miR-21 and TNF-α, and found that they are both expressed at the invasive front of colon cancers and are often co-detected in budding cancer cells and cancer cells considered to be part of branching events, however, the co-localization analysis of the four cases did not show consistent co-expression or converse expression patterns.