Monitoring changes of collagen fibers surrounding breast ductal carcinoma in situ using multiphoton microscopy

Ductal carcinoma in situ (DCIS) accounts for approximately 20% of all breast cancer. DCIS is a form of breast cancer that is restricted to the ducts and has not invaded surrounding breast tissue or spread to lymph nodes or other parts of the body. The grades of DCIS are classified as low, intermediate, and high, based on cytonuclear features, and high-grade DCIS has a higher risk of progressing into invasive ductal carcinoma (IDC). The collagen fibers are an important component of the tumor microenvironment (TME) in DCIS and play an important role in tumor formation and progression. Multiphoton microscopy (MPM) based on second harmonic generation (SHG) and two-photon excitation fluorescence (TPEF) can monitor the morphological changes of collagen fibers around DCIS. SHG is currently considered the gold standard for visualizing collagen fibers and has been widely employed in various cancer-related studies of collagen fibers. Our investigation employed MPM imaging of breast tissue to observe the differences in collagen fibers within three distinct grades of DCIS. Through image processing, we were able to quantify various attributes of collagen fibers enveloping DCIS lesions of varying grades. The study found that collagen fibers surrounding low-grade DCIS were denser and exhibited more sinuous shapes, whereas collagen fibers around intermediate and high-grade DCIS lesions were less dense and exhibited a more organized arrangement. The study suggests that MPM imaging is a powerful tool for investigating the microenvironment of DCIS and may provide valuable information for predicting disease progression and prognosis.