Label-free FTIR spectroscopy detects and visualizes the early stage of pulmonary micrometastasis seeded from breast carcinoma

Abstract

An application of FTIR spectroscopic imaging for the identification and visualization of early micrometastasis from breast cancer to lungs in a murine model is shown. Spectroscopic and histological examination is focused on lung cross-sections derived from animals at the early phase of metastasis (early micrometastasis, EM) as compared to healthy control (HC) and late phase of metastasis (advanced macrometastasis, AM) using murine model of metastatic breast cancer with 4T1 cells orthotopically inoculated. FTIR imaging allows for a detailed, objective and label-free differentiation and visualization of EM foci including large and small micrometastases as well as single cancer cells grouped in clusters. An effect of the EM phase on the entire lung tissue matrix as well as characteristic biochemical profiles for HC and advanced macrometastasis were determined from morphological and spectroscopic points of view. The extraordinary sensitivity of FTIR imaging toward EM detection and discrimination of AM borders confirms its applicability as a complementary tool for the histopathological assessment of the metastatic cancer progression.

Keywords: Chemometrics; Early micrometastasis; FTIR spectroscopy; IR imaging; Pulmonary metastasis of breast cancer.