Breast Pathology and Cancer Diagnosis

Biography

Biography: Layane Duarte e Souza

Abstract

Breast cancer is the most common cancer in Canadian women. Currently, diagnosis is based on immunohistochemistry to identify cells expressing estrogen and progesterone receptor (ER and PR) and human epidermal growth factor receptor 2 (HER2). This strategy targets cancer cells to determine the different molecular subtypes and requires one tissue section per marker. Until now, there is no option to detect all markers in the same section. Hence, determination of infiltrated lymphocytes in the tumor microenvironment is a crucial step to guide immunotherapy in combination with chemotherapy. The single detection would be costly and delay the diagnosis, which impairs the application of tumor landscapes in clinics. The development of simultaneous detection in one tissue section is fundamental to achieve the safe implementation of personalized treatment. Raman spectroscopy imaging emerges as a choice for simultaneous detection of these markers. Raman probes based on single-walled carbon nanotubes (SWCNT) have a unique spectrum, peaks widths of about 2 nm and non-bleaching signal. Each tube (~200nm length, 1.4nm diameter) contains internalized fluorescent dye (β-carotene, sexithiophene) emitting a specific Raman signature. The SWCNT were functionalized with an amine-polyethylene glycol-carboxylic acid (NH2-PEG-COOH) to allow the attachment of antibodies anti-ER and anti-HER2. Immunogold labeling confirmed the attachment of the antibody in the right orientation. Raman probes were used in formalin-fixed paraffin-embedded (FFPE) breast cancer tissues ER+ and HER2+; also in cell lines MCF-7 (ER+) and SKBR-3 (HER2+). IHC results using tissue and cell lines were compared to Raman imaging to evaluate probes sensitivity and specificity. Preliminary results show that anti-ER and anti-HER2 attach in both tissue and cells; however, the Raman signal is weak, compared to IHC. Currently, we are optimizing the Raman probe to obtain a better signal, as well as optimizing the Raman probe incubation with tissues.