Are breast tumours innervated? Immunohistological investigations using antibodies against the neuronal marker protein gene product 9.5 (PGP 9.5) in benign and malignant breast lesions.

The aim of the present study was to assess the innervation pattern of benign and malignant breast lesions using the neuronal marker protein gene product (PGP) 9.5. An unlabelled antibody technique (using streptavidin biotin complex formation) was used on paraffin wax sections of tissues fixed in neutral buffered formalin. In 2/4 cases of chronic mastopathy, PGP 9.5 immunoreactivity was seen in relation to blood vessels and the ductal system. No immunoreactivity for PGP 9.5 was seen in the affected tissues of 9/10 cases of fibroadenomata. In 9/16 breast cancers, PGP 9.5-labelled perivascular nerve fibres were detected in connective tissue stroma supporting carcinoma tissue, though not in the immediate vicinity of such tumour tissue. Labelled nerve fibres were detected in large bundles at the periphery of tumours, possibly unrelated to the latter. Our results indicate that the newly formed blood vessels within a tumour are not innervated, though major blood vessels which supply the tumour are innervated.