TLR4 and necrotizing enterocolitis: However, these models may have more value in uncovering the underlying mechanisms that lead to NEC in the subset of term and breastfed patients who develop the disease, or in those cases in which TLR4 activation may not be the inciting event, such as in cases of viral, fungal and Gram-positive NEC that have been reported (Coggins et al., 2015).