Midkine and pleiotrophin concentrations in needle biopsies of breast and lung masses.

BACKGROUND/OBJECTIVE: Midkine (MDK) and pleiotrophin (PTN) are two closely related heparin-binding growth factors which are overexpressed in a wide variety of human cancers. We hypothesized that the concentrations of these factors in washout of biopsy needles would be higher in breast and lung cancer than in benign lesions. METHODS: Seventy subjects underwent pre-operative core needle biopsies of 78 breast masses (16 malignancies). In 11 subjects, fine needle aspiration was performed ex vivo on 7 non-small cell lung cancers and 11 normal lung specimens within surgically excised lung tissue. The biopsy needle was washed with buffer for immunoassay. RESULTS: The MDK/DNA and the PTN/DNA ratio in most of the malignant breast masses were similar to the ratios in benign masses except one lobular carcinoma in situ (24-fold higher PTN/DNA ratio than the average benign mass). The MDK/DNA and PTN/DNA ratio were similar in most malignant and normal lung tissue except one squamous cell carcinoma (38-fold higher MDK/DNA ratio than the average of normal lung tissue). CONCLUSIONS: Both MDK and PTN are readily measurable in washout of needle biopsy samples from breast and lung masses and levels are highly elevated only in a specific subset of these malignancies.