Abstract P5-04-27: The relationship between tumour associated macrophage markers and tumour, demographic & behavioural factors in breast cancer

Abstracts: 2019 San Antonio Breast Cancer Symposium; December 10-14, 2019; San Antonio, Texas BACKGROUND: Tumour associated macrophages (TAMs) are prognostic markers in breast cancer, however the influence of patient demographic and behavioural factors on these inflammatory markers has not been fully appreciated. METHODS: In 201 invasive breast cancer and 58 ductal carcinoma in-situ (DCIS) patients, TAM density (percentage % CD68 [IHC-immunohistochemistry] positive cells) was correlated with tumour factors (grade, proliferation (Ki67), ER, HER2); demographic factors (age, menopausal status, breast density, BMI, diabetes) and behavioural factors (smoking, alcohol). RESULTS: TAM density was increased in invasive breast cancer, compared to DCIS, and normal tissue distant from the tumour (59%, 41% and 6% respectively; p<0.001). In invasive cancer, TAM density increased with increasing tumour grade (Grade 1: 42%, Grade 2: 58%, Grade 3: 72%; p=0.006), high Ki67 (71% vs. 47%; p=0.004), ER negativity (70% vs. 51%; p=0.02) and HER2 (HER2 positive 77% vs. HER2 negative 55%; p=0.055). TAM density was higher in high compared to low/intermediate DCIS (44% % vs 31% respectively). In terms of demographic factors, TAM density did not correlate with age, menopausal status, breast density (BIRADs), BMI or history of diabetes. TAM density was not increased in patients who smoked; however, it was increased in patients who self-reported alcohol intake (non-drinker 43% vs. drinker 62%; p=0.01). CONCLUSION: TAM density shows utility in identifying aggressive breast cancer sub-types. The association reported between TAM density and alcohol intake suggests a possible mechanism for alcohol as a risk factor for breast cancer. Citation Format: Urvashi Singh, John Castle, Sophie Greenhalgh, Umar Hussain, Tine Descamps, Sarah Nash, Mary Wilson, Roger Hunt, Cliona C Kirwan. The relationship between tumour associated macrophage markers and tumour, demographic & behavioural factors in breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-04-27.