Friday, November 18, 2011

Microscope can see inside cells, predict cancer

A newly developed nanomicroscope differs from conventional light microscopy by the fact that it allows us to 'see' what is inside our cells. Because cellular structures are too small to see with ordinary light waves, scientists from the Northwestern University in Illinois used a trick that allows them to reconstruct an image from the reflection of the light that passing through a cell. Light waves are altered in accordance with the density of the material it passes through, and the difference in reflection is what the images are based upon. By constructing a view of what is going on inside a cell, it should be easier to spot changes that can eventually lead a cell to become cancerous. If this proves to be effective in the clinic, we can kill cancer before it starts.

The new microscope was tested on a set of different cell types, which included those of a cancerous type. By analysing the reflection patterns of the cellular DNA, scientists were able to show that the structure packing our genetic code, dubbed chromatin, differs between healthy and cancerous cells. It can be used to distinguish healthy and malicious cells for various different organ types, which indicates that the newly developed form of microscopy is a robust tool for future use in the oncology department.

To prove that the light reflection microscope can accurately predict cancer, instead of just recognizing it, the scientists swabbed some cells from the cheeks of 135 smokers, and analysed them. The microscope was found to correctly predict which people have lung cancer, and those that are cancer-free. The same result was found for a rectal swab to detect colon cancer, and a cervical swab to uncover ovarian cancer. That is a promising result for clinical use, especially because the testing procedure is not very invasive.

Cancer is in essence a disease of the DNA. To become cancerous, mutations in our genetic code are required, which cells can acquire in various ways. The first one is to alter the genetic code itself, which can make a cancerous gene (an oncogene) more active, or inhibit the function of a tumour-suppressor gene. In addition, the chromatin structure that is used to wind up our DNA can be loosened or tightened, which corresponds to more or less activity of the genes that are found on that particular piece of chromatin.

Chromatin studies are bundled in a field called epigenetics. This describes the form of genetics that is inheritable, but does not revolve around the genetic code. By adding certain chemical groups, the structure of the chromatin can chance, influencing the capability of the cellular machinery to 'read' the genes that are present on the affected part of the genome. Recent studies have revealed that heritable epigenetic modifications can increase your life span, cause obesity or reveal the living conditions during the period you grew up. Moreover, epigenetic therapies are being tested for their use in treating cancer.

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