New imaging technologies promise the chance for even earlier detection of cellular abnormalities linked to cancer, according to a study recently published in the journal Cancer Research by Vadim Backman of Northwestern University.
Light microscopy traditionally used to detect changes in cell or tissue structure associated with cancer is limited by the wavelength of light – structures that are smaller than the 400 nanometers (one billionth of a meter) cannot be resolved. Partial wave spectroscopic (PWS) microscopy, in contrast, enables this level of resolution. Instead of directly visualizing cell structures as in traditional microscopy, PWS microscopy looks at how light beams interact within a cell – as beams travel through a cell they interact with different structures within the cell. Light beams are reflected off of or absorbed by these structures differently according to differences in the structures’ density. These patterns of light reflection are reconstructed via computer software in order to distinguish the cell’s nanoscale architecture.
This highly sensitive visualization may prove invaluable in detecting subtle changes that may occur in cancer cells long before a tumor is visible. One subtle change that PWS can detect is changes to the structure of chromatin – the complex of DNA and proteins that make up chromosomes. Changes in how tightly the protein portion of chromatin binds to the DNA portion can influence what genes are used, and how often – so it’s not surprising that preliminary research from the Backman lab using PWS to examine seemingly healthy cells from patients with lung cancer show changes in the chromatin structure.
Studies are ongoing to determine if similar changes are detected in other types of cancer cells. PWS is still years away from use as a routine clinical diagnostic, but it may one day offer clinicians an additional cancer screening tool in at-risk patients.