Combined evaluation of NGF and p75NGFR expression is a biomarker for predicting prognosis in human invasive ductal breast carcinoma

Nerve growth factor (NGF) is a member of the neurotrophin family and is ess ential for the differentiation and maintenance of neural cells. Recently, i t has been reported that NGF is involved in the growth of breast cancer. On the other hand, two types of NGF receptors have been identified. a low-aff inity receptor, p75NGFR, and a high-affinity receptor, TrkA. NGF-p75NGFR in teraction is known to play an important role in apoptosis, whereas NGF-TrkA interaction is responsible for the survival of neural cells. We examined t he relationship between clinicopathological factors, Ki-67 index, apoptotic index and the immunohistochemical expression of NGF, TrkA and p75NGFR in 7 1 invasive ductal breast carcinoma (IDBC) specimens. Our data indicate that positive Ki-67 expression (a labeling index exceding 30%) correlates signi ficantly with the positive expression of NGF (p=0.0091). Moreover, the apop totic index was found to correlate with a strong expression of p75NGFR. Fur thermore, patients who were NGF positive and p75NGFR negative had significa ntly poorer disease-free survival rates (p=0.0165). In contrast, those who were NGF negative and p75NGFR positive had significantly more favorable out comes (p=0.0191). These findings suggest that a combined evaluation of NGF and p75NGFR expression is a predictive factor in the prognosis of IDBC pati ents.