Scripties UMCG - Rijksuniversiteit Groningen
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Een verstoring in de balans van tumor-geassocieerde macrofagen leidt tot ongunstige tumorkenmerken in HER2-positief mammacarcinoom

(2017) Zwager, M. (Mieke)

Breast cancer is the most prevalent invasive malignancy in women worldwide. Human
Epidermal growth factor Receptor 2 (HER2) is amplified in 15-20% of breast cancers. HER2
positive breast cancer is highly aggressive and associated with poor prognosis, rapid
spreading and has high recurrence rates and poor survival. Over the last few years treatment
has improved, but prognosis remains unsure. It is thought that the tumour microenvironment
and its tumour-associated macrophages are of great importance in cancer development and
progression. It is suggested that under physiological conditions a balance exists between antitumour
M1 macrophages and pro-tumour M2 macrophages. In this research the relation
between disturbance in this balance and clinicopathological characteristics of HER2-positive
breast cancer was investigated. Digital image analysis was used to count the amount of M1
macrophages and M2 macrophages and to calculate the M2:M1 ratio in 106 primary HER2-
positive breast cancers. We found a higher mean count of M2 macrophages compared to M1
macrophages in tumours. Therefore a high mean M2:M1 ratio was found. An increase in the
number of M2 macrophages and a higher M2:M1 ratio were significantly correlated with high
tumour grade. Low macrophage count was significantly related with higher expression of
androgen- and estrogen receptors. Significant correlations with overall survival and relapse
free survival were not found. These results suggest that there indeed is a disbalance between
subgroups of tumour-associated macrophages in HER2 positive breast carcinomas. This
disbalance may play a role in the development of poor tumour characteristics.

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