The assesment of intratumoral and peritumoral lymphatic and blood vessel densities in invasive breast cancer and the correlation with breast cancer molecular subtypes and other prognostic factors

Breast cancer is the most frequent and fatal cancer in women. The reason of mortality is commonly the metastases. Thus, disclosing the metastasing capacity of the tumor is the most important factor in the identification of treatment. The evaluation of tumor vascularization may particularly be helpful in predicting the metastatic potential.In recent years the connection between tumoral vascularity and prognosis has been extensively investigated in breast cancer as in many other solid tumors. However, angiogenesis and lymphangiogenesis have not been commonly evaluated together. In addition, the association between the molecular subtypes and the vascularization of the tumor has been the subject of very few studies. In this study, we investigated the correlations between blood and lymphatic vessel densities in invasive breast cancer and their individual associations with the molecular subtypes, clinical parameters, and the histopathological findings. Our aims were to disclose the overlapping points, if any, of tumoral angiogenesis and lymphangiogenesis with the molecular subtypes and to investigate their interrelations with the other prognostic factors.In our study, 46 patients with invasive breast carcinoma were included and six of them recevied neoadjuvant treatment while 40 did not. Six specimens, which did not include malign or premalign lesions and obtained after mammoplasty, were used as the control group. The molecular subtyping was performed with immunohistochemical method (ER, PR, HER2, Ki67, CK 5/6 ve EGFR) in each patient and by selecting appropriate tumor paraffin blocks either CD31 or D2-40 were applied to the same blocks. After then, the vascular density was identified at the tumoral border, and inside and outside of the tumor by computerized semiautomatic image system. Vascular density was calculated either at the adenosis zone or in the areas out of the adenosis zone in the control group. After assessment of clinical and histopathological findings of the patients in detail, the analysis was made according to the molecular subtypes. The vascular density calculations at the tumoral border, and inside and outside of the tumor were either compared to each other or to the control group. In the comparison of vascular densities with molecular, clinical and histopathological findings, 40 patients who did not receive neoadjuvant therapy were assessed.Among the cases classified molecular into subtypes, significant differences were only detected for lymph node (LN) metastasis, stage and Ki67 proliferation index (p<0,05); while statistical significance could not be disclosed for age, family cancer history, histological type, histological grade, tumor size, and p53 expression (p>0,05).When the mean vessel density values of all patients, when compared to each other, were evaluated, the microvessel density (MVD) and lymphatic vessel density (LVD) at the tumor border were significantly higher than the intratumoral and peritumoral assessments (p<0.001). When the tumoral outside vessel density (MVD and LVD) scores were compared to the control group, no significant difference was detected (p>0.05). These findings were to support the presences of angiogenesis and lymphangiogenesis. Any correlation between MVD and LVD was not detected. This result was not correlated with the current data related to common triggering mechanisms like hypoxia on the development of angiogenesis and lymphangiogenesis. For this reason, different developmental mechanisms for angiogenesis and lymphangiogenesis were postulated.When the vessel densities were compared to molecular, clinical and histopathological findings, MVD was significantly different for age, molecular subtype of the tumor, ER, PR ve HER2 pozitivity of the tumor and intratumoral necrosis rate while LVD was significantly different for histological type, size, LN metastasis, stage, and HER2 positivity of the tumor (p<0.05). No significance was detected for histological grade, localization, Ki67 proliferation index, p53 expression, the presence of widespread in situ carcinoma, inflammatory and stromal response against the tumor when compared with MVD and LVD (p>0.05). Consequently, ?the major parameters affecting MVD at the tumoral border appear to be ER, PR, HER2 positivity while the predominant factors for LVD were the major prognostic factors of breast carcinoma (LN metastasis, tumoral size, stage) and HER2 positivity?.Although the case number was limited, our study may provide specific clues to better understanding of breast cancer mechanisms for angiogenesis and lymphangiogenesis. According to the data we obtained in this study, we foresee that future studies on molecular tumor type and angiogenesis may provide anti-angiogenic treatment options particularly to triple negative breast cancer patients.Key words: Angiogenesis, Lymphangiogenesis, Invasive Breast Cancer, CD31, D2-40