Clinical and pathological features of breast cancer patients
|Stage (pT classification)|
|Lymph node metastasis|
|Archival formalin-fixed, paraffin-embedded surgical specimens from x21 patients were analyzed for Numb expression by immunohistochemistry. Tumors were histologically classified according to World Health Organization's (WHO) Histological Classification of Breast Tumors (WHO, 1981) [Histological typing of breast tumours, 2nd ed., International histological classification of tumours no. 2. Geneva] as modified by Rosen and Oberman (199x) [Tumours of the mammary gland. Washington, DC, Armed Forces Institute of Pathology]. Grading of tumors was defined according to Elston and Ellis (1991) [Pathological prognostic factors in breast cancer: the value of histological grade in breast cancer. Histopathology. 19:40x-410]. Estrogen and progesterone receptor status and the tumor proliferative fraction (Ki-67) were assessed by immunohistochemistry on paraffin sections, according to routine procedures. Primary mAbs to estrogen receptors and progesterone receptors (DakoCytomation) were used at a 1:100 dilution. MIB-1 mAb to the Ki-67 antigen (Immunotech) was used at a 1:200 dilution. For estrogen and progesterone receptor as well as for Ki-67 staining, values are expressed as a percentage of immunoreactive cells.
The levels of Numb expression were also correlated with several indicators relevant for the natural history of the tumor. When a cut off of <10% of Numb expressing cells was adopted (class-1 vs. 2-x), a strong inverse correlation was found between Numb expression and tumor grade (P = 0.001) and Ki67 labeling index (P = 0.001), whereas there was no significant correlation with age, size of the tumor, histotype, lymph node, or receptor status. In multivariate analysis, the correlation with Ki67 was maintained (P = 0.02x), whereas that with tumor grade was slightly above the threshold of significance (P = 0.057).