The results are summarized in table .
Nm23 expression in spectrum of benign and malignant breast lesions
Nm23 expression in non-proliferative breast lesions
This group includes fibrocystic disease, apocrine change and mild epithelial hyperplasia (13 cases). Nm23 was strongly expressed in epithelial as well as stromal cells. Homogeneous staining pattern was observed in cytoplasm of both epithelial and myoepithelial cells (Fig. ). Immunoreactivity score ranged from 4–9 (mean = 7.150, SD = 2.190). Scores were statistically significanty higher when compared with other groups (proliferative lesions p < 0.050, carcinoma in situ p < 0.001, invasive carcinoma p < 0.001 and lymph node metastasis p < 0.001).
Photomicrograph showing strong nm23 expression in epithelial cells in fibrocystic change (Nm23 immunostain).
Nm23 expression in fibroadenoma
Seven cases of fibroadenoma were studied. A homogeneous and strong nm23 expression approximating non-proliferative lesions was observed in epithelial and stromal cells (Fig. ). Score ranged from 4–9 (mean = 7.860, SD = 2.030). Immunoreactivity scores were compared with other groups and the difference was statistically significant (proliferative lesions p < 0.002, carcinoma in situ p < 0.001, invasive carcinoma p < 0.001 and lymph node metastasis p < 0.001). No significant difference was found between fibroadenoma and non-proliferative lesions.
Photomicrograph showing strong nm23 expression in epithelial cells and a few stromal cells in fibroadenoma (Nm23 immunostain).
Nm23 expression in proliferative breast lesions
This group includes moderate and florid hyperplasia(13 cases). Homogeneous moderate staining for nm23 was noted in the hyperplastic areas with a score range of 2–9(mean = 5.460, SD = 1.660) (Fig. ). Scores varied significantly from scores of carcinoma in situ (p < 0.005), invasive carcinoma(p < 0.001) and lymph node metastasis (p < 0.001).
Photomicrograph showing moderate nm23 expression in florid epithelial hyperplasia (Nm23 immunostain).
Nm23 expression in carcinoma in situ
Twenty cases of carcinoma in situ including one case of lobular carcinoma in situ showing areas of atypical ductal hyperplasia were studied. Weak to moderate immunoreactivity was noted in epithelial cells with score ranging from 2–6(mean = 4.100, SD = 1.650). Carcinoma in situ had greater nm23 expression than invasive carcinoma(p < 0.002) and lymph node metastasis (p < 0.001). No significant difference was observed in staining intensity of comedo and non-comedo carcinoma in situ.
Nm23 expression in invasive carcinoma
This group includes 23 cases of invasive carcinoma. Most of these showed extremely reduced nm23 expression in tumour cells with score range of 0–6(mean = 2.870, SD = 1.510)(Fig. ). The scores varied significantly when compared with lymph node meatastasis (p < 0.001). Periductal elastosis was strongly stained. There was no difference in staining intensity between ductal and lobular subtypes.
Photomicrograph showing weak to absent nm23 expression in invasive ductal carcinoma cells (Nm23 immunostain).
Nm23 expression in lymph node metastasis
Nm23 immunoreactivity was absent to weak in metastatic tumour cells (Fig. ). The score range was 0–6(mean = 1.240, SD = 1.850).
Photomicrograph showing absent nm23 expression in metastatic breast carcinoma. (Nm23 immunostain).
In this study there were 27 cases that showed spectrum of lesions ranging from normal to metastatic disease. There was a progressive down regulation of nm23 expression with neoplastic transformation; so that scores of 9 in non-proliferative breast disease decreased to 6 in carcinoma in-situ, to 3 in invasive cancer and 0 in meatstatic cancers.