Immunohistochemical expression of CD34, Smooth muscle actin and Type IV collagen in breast carcinoma (A Clinicopathological Study)

Breast cancer is the most common cancer in women world wide, it is now the most common leading cause of death in women aged above 35 years both in developed and developing regions . In Iraq, breast cancer is the commonest type of female malignancy, accounting for approximately one-third of the registered female cancers. Tumor angiogenesis is the development of new blood vessels from an existing vascular network, its a prerequisite for tumor growth beyond 2 mm in diameter and play an important role in metastasis and prognosis of the tumors including breast cancer. Angiogenesis can be quantitated by staining histological sections with antibodies that specifically identify endothelial cells. CD34 is a sensitive marker for vascular endothelium. The number of microvessels can be estimated by many methods including hot spot method .Aim of the study: The aim of this study is to evaluate the angiogenesis in breast carcinoma by measuring microvascular density (MVD) with CD34 and it`s maturity with SMA immunohistochemical method and to correlate this with clinicopathologic parameters and to study basement membrane invasion by tumor cells using IHC for type IV collagen. Patients, materials and methods: Fifty seven cases were included in the this study, 5 benign and 52 malignant. All formalin fixed paraffin embedded tissues were retrieved from archived files of department of pathology of Al-Kadhemia Teaching Hospital (for the period between Jan. 2010-Nov. 2010) and Teaching Lab. Of Medical City Hospital (for the period between Jan. 2009-Oct. 2009). For each case 4 sections of 5 μm thickness were taken ,one for H&E and others for immunohistochemistry (CD34, collagen IV, SMA) . Clinical informations regarding age, tumor size, grade, histological subtype, lymph node involvement, and lymphovascular permeation were studied. Counting the number of microvessels was done by hot spot method , scanning of the tumor sections at low power (X4) first to identify hot spots then counting was done on (X40) .Three hot spot areas were selected and the mean number of microvessels was calculated. Results : In this study , the mean MVD in benign cases was (45.60+ 7.54) while in malignant cases was (91.55+3.93). The difference in MVD between benign and malignant cases was significant (P= 0.001) . Regarding histological type of the tumor lower MVD in insitu carcinoma (for DCIS MVD was 59 and for DCIS+LCIS MVD was 66) than in invasive carcinoma ,IDC(NOS)= 93.74 •Regarding the age, there is no significant correlation between MVD and the age of patients(negative correlation not significant) as r= -0.063 and p= 0.656. Regarding the tumor grade, the difference in MVD between grade II (88.94+4.35) and grade III (97.43+8.27) was statistically not significant(P=0.324). •Regarding the tumor size ,the MVD for tumors<2cm (T1) was (78.40+3.43) , for tumors 2-5cm (T2) MVD was(102.09+6.57) and for tumors >5cm MVD was(86.55+6.37). The difference in MVD between T1, T2 and T3 was statistically not significant(P=0.052) . •For the L.N. ,the difference in mean MVD between positive L.N. involvement (97.60+5.46) and negative L.N. involvement (79.11+2.46) was statistically significant (P=0.004). •For lymphovascular permeation ,the difference in mean MVD between positive lymphovascular permeation (95.20+4.52) and negative lymphovascular permeation (74.11+3.55) was statistically significant(P=0.001). Conclusion: 1. Assessment of tumor vascularity by CD34 , SMA immunohistochemistry is valuable in quantifying angiogenesis and its maturity in breast carcinoma.
2. MVD is higher in malignant than in benign breast lesions, with significant correlation between MVD in benign and malignant lesions. 3.Higher MVD was noticed in invasive carcinoma, T2, grade III, positive L.N. involvement and lymphovascular permeation. 4.MVD is significantly correlated with L.N. involvement and lymphovascular permeation. 5.No statistical significant correlation between MVD and age of patient, tumor size, tumor grade. 6. Measurements of angiogenesis may have clinical utility in the evaluation of breast cancer, particularly for estimation of metastatic risk. A high MVD may be a poor prognostic marker of breast carcinoma and a target for antiangiogenic therapy.