Pioneering biophotonics technology developed in the US can detect nanoscale changes in cells from the cervix and uterus that may indicate early stage ovarian cancer, according to a study published this month in the International Journal of Cancer.

The researchers describe how using partial wave spectroscopic (PWS) microscopy they could detect diagnostic changes in uterus and cervix cells taken from ovarian cancer patients via a minimally invasive procedure. Under an ordinary microscope, the cells would look normal.

PWS has already shown promise in previous studies as a way to detect colon, pancreatic and lung cancers early, also using, as in this study of ovarian cancer, cells from neighboring organs.

The cells for this latest ovarian cancer study came from the cervix and uterus. For the earlier lung cancer study, the researchers used cells brushed from the cheek. For the colon cancer study, cells came from the rectum, and for the pancreatic cancer study, they came from the duodenum.

In all cases, cells from these neighboring organs showed changes at the nanoscale when cancer was present.

If commercialized, the researchers, from Northwestern University and NorthShore University HealthSystem (NorthShore) in Evanston, Illinois, believe the method could be in clinical use in around five years.

"This intriguing finding may represent a breakthrough that would allow personalization of screening strategies for ovarian cancer via a minimally intrusive test that could be coupled to the Pap smear," says co-author Hemant K. Roy, of NorthShore.

There is currently no reliable way to detect ovarian cancer in its early stages. The majority of cases are not diagnosed until the cancer has spread to the lymph nodes, vastly reducing the chances of a cure and making it very difficult to treat.

PWS works at the nanoscale, which is much, much smaller than the scale of an ordinary microscope. A nanometer is one billionth (10 to the minus 9) of a meter, or about three to five atoms wide (a virus is typically 100 nm in size).

At this scale, the behavior of particles and materials is governed more by what scientists call quantum effects, giving them a new bag of tools to work with.

PWS uses light scattering to probe the nanoscale architecture of cells ("nanocytology"), offering scientists what the authors describe as a "paradigm shift" in biomedical optics.

"Technologically, we demonstrate that PWS nanocytology is exquisitely sensitive to cell nano-architecture at length scales <300nm," they write.

Roy and colleagues describe how PWS detected profound changes that are the earliest known signs of cancer: changes that can be seen in cells far from the tumor site, or even before a tumor starts to form.

Corresponding author Vadim Backman, who developed PWS at Northwestern, says:

"We were surprised to discover we could see diagnostic changes in cells taken from the endocervix in patients who had ovarian cancer. The advantage of nanocytology -- and why we are so excited about it -- is we don't need to wait for a tumor to develop to detect cancer."

PWS can identify cell features as small as 20 nm, allowing scientists to assess the amount of disorder in the nanoscale organization of a cell, something known to be a strong marker for the presence of cancer either in the same or nearby organ.

A test based on PWS would make use of what the researchers term the "field effect", which is the extent to which cells far from the malignant or pre-malignant tumor show molecular and other changes.

For this latest study, Roy, Backman and colleagues tested endometrium (part of the uterus) cells from 26 patients (11 with ovarian cancer and 15 controls), and endocervix cells from 23 patients (10 with ovarian cancer and 13 controls).

They put the cells on slides and then examined them with PWS. The nanoarchitecture of cells from cancer patients was significantly more disordered than that of the controls in both the endometrium and the endocervix groups.

Backman and Roy have been working together for over ten years, and have been conducting clinical trials with PWS for four of them.

"The changes we have seen in cells have been identical, no matter which organ we are studying," says Backman.

"We have stumbled upon a universal cell physiology that can help us detect difficult cancers early. If the changes are so universal, they must be very important," he adds.

In another recent example of nanotechnology in medicine, scientists in the US writing in Nature Nanotechnology, describe how they developed "nanosponges" disguised as red blood cells that can mop up dangerous toxins in the blood.

Written by Catharine Paddock PhD