Detecting and Quantifying Biomarkers of Risk for Colorectal Cancer Using Quantum Dots and Novel Image Analysis Algorithms

Abstract

Colorectal cancer, the second leading cause of cancer deaths in the United States, is a molecular disease that is largely lifestyle determined and preventable. While heart disease has been sharply declining, in large part from widespread use of biological measurements that indicate risk ("biomarkers of risk"), such as blood cholesterol, to motivate and guide preventive treatment, colorectal cancer is a disease for which mortality rates have changed little and for which there have been no biomarkers of risk. Based on new knowledge about the molecular basis of colorectal cancer we developed and validated a panel of treatable biomarkers of risk that can be measured in rectal biopsies using automated immunohistochemistry and semi-automated image analysis. The methodology is now being made practical for clinical application through the use of 1) quantum dots, so that all of the biomarkers can be detected simultaneously on the same histologic sections (i.e., multiplexed), and 2) novel, automated image analysis algorithms to measure the quantities and tissue distributions of the biomarkers. Herein we summarize our methods, results, current directions, and progress.

Nanoparticle Transport from Mouse Vagina to Adjacent Lymph Nodes

“…The Fourier transform of each image was taken and the derivative in frequency space was calculated. This eliminated low frequency signals and upon calculating the inverse Fourier transform, the image no longer had the “haze” of the autofluorescence from the lymph node itself [50]–[54]. After the autofluorescence removal, it is easier to identify aggregates of Q-dots.…”

TGF-α Expression as a Potential Biomarker of Risk Within the Normal-appearing Colorectal Mucosa of Patients with and without Incident Sporadic Adenoma

“…2) used to describe and quantify various characteristics of the labeled antigens in the colon crypts is an image analysis scoring procedure for antigens that are labeled with a wide range of intensities in gradient distributions along the crypt axis (31). Methods and staining protocols are fine-tuned to achieve ideal staining quality within the tissue for quantification using our custom-designed plug-in into ImagePro Plus image analysis software (Media Cybernetics, Inc.), a light microscope, digital camera, and drawing board.…”

Recent developments in multiplexing techniques for immunohistochemistry

“…The use of quantum dots (Figure 4A) is an effective signal enhancement method, often applied to multiplexed IHC, that offers several advantages over traditional fluorescent proteins and organic dyes [61], [62]. These semiconductor nanocrystals are usually <10 nm in diameter and exhibit a narrow fluorescence emission spectrum [63], high photostability [64], and a symmetric emission spectrum [65].…”