Immunocytochemical analysis of p63 and 34βE12 in fine needle aspiration cytology specimens for breast lesions: a potentially useful discriminatory marker between intraductal papilloma and ductal carcinoma in situ.

OBJECTIVE

We applied immunocytochemistry to fine needle aspiration (FNA) breast lesion slides in an attempt to enhance their objectivity and specificity.

METHODS

We analysed 56 FNA specimens from patients with histologically confirmed breast lesions, using 34βE12 and p63 antibodies. Immunostained slides were examined in terms of both solitary positive cells (within clusters and non-clusters) and positive clusters within a slide.

RESULTS

Positive scores (≥2) for p63(+) cells and percentages of p63(+) clusters differed significantly (P < 0.001) between malignant (3 of 34; 9%) and benign (11 of 22; 50%) cases and varied between benign and malignant groups: intraductal papilloma (IDP) (2 of 8), other benign lesions (9 of 14), ductal carcinoma in situ (DCIS) (1 of 11) and invasive carcinoma (IC) (2 of 23). Similarly, 34βE12 scores were higher in benign cases (IDP, 8 of 8; other benign, 9 of 14) than in malignant cases (DCIS, 1 of 11; IC, 3 of 23). As well as a significant difference between benign and malignant cases (17 of 22, 77% versus 4 of 34, 12%; P < 0.001), the percentage of 34βE12(+) clusters was significantly higher in IDP compared with DCIS (P = 0.001).

CONCLUSIONS

The immunostaining of FNA breast specimens for p63 and 34βE12 may help in difficult diagnoses.