Recognizing cancer diseases at an early stage: Researchers develop label-free automatic cancer diagnostics

October 25, 2013, Ruhr-Universitaet-Bochum
pectral histopathology: Fourier transform infrared (FTIR) and Raman imaging analyses of tissue sections of a colorectal carcinoma (colon tumour). Image magnification increases from the top down. A classic H&E-(haematoxylin-eosin)-stained section is shown on the right. FTIR imaging (left) achieves a resolution of ten micrometres at maximum; spectral histopathology reveals the existence of alterations in the crypts (red), i.e. depressions in the colon, which are confirmed by immunohistochemical fluorescent stain (P53). In order to analyse the crypt alterations in more detail, the researchers applied Raman imaging with a higher spatial resolution (bottom row). Altered nuclei (grey) in the altered crypts (red) can be identified here in comparison with a fluorescent stain (P53, green). Credit: RUB, picture: Faculty of Biophysics

Researchers at the Ruhr-Universität Bochum (RUB) have developed a new spectroscopic method to support pathologists in diagnosing cancer. In the Journal of Biophotonics and the Analyst they compared conventional procedures for colon cancer identification with a novel method called label-free spectral histopathology. "Contrary to previous methods we no longer have to stain the tissue in order to detect cancer," says Professor Klaus Gerwert from the Protein Research Unit Ruhr within Europe (PURE) at the RUB. "In the future, this will give us the opportunity to classify a tissue sample automatically as being either normal or diseased."

Diagnosis: Colon cancer

Today pathologists slice tissue obtained from biopsies into thin sections, stain them chemically, and eventually identify by visual inspection under the microscope. This is usually done at an advanced stage of the disease, and the method provides no information about the molecular causes of the tumour. However, the method of spectral histopathology (SHP) established at the RUB Department of Biophysics captures molecular alterations directly in the tissues, especially changes of proteins. It works without any labelling agents, such as fluorescent dyes. SHP may even detect alterations occurring in early tumour stages. Since the analysis uses light beams, SHP is not limited to thin sections of biopsy specimens – in fact, one can apply the method directly in live tissue, where it allows to inspect a site of interest with the aid of fibre-optics. "In the future, we intend to work together with clinical partners and apply spectral histopathology to patients directly via endoscopes," says Klaus Gerwert.

How spectral histopathology works

In SHP, researchers record spatially resolved vibration spectra of a tissue using either an infrared or a Raman microscope. A vibration spectrum reflects the condition of all proteins in a tissue at the site measured. Alterations induced by cancer are reflected in the respective spectrum. The spectrum is thus representative of the status of the sample, just like a fingerprint is characteristic of an individual person. Approximately ten million infrared spectra are usually recorded to produce one single tissue image. Using sophisticated computational image analysis procedures, researchers compare these spectra with a reference database. This database contains spectra of already known tissues and tumours, and has been established in the PURE consortium as a collaboration between pathologists, biophysicists and bioinformaticians. The analytical programme allocates each spectrum to tissue types that have been stored in the database, represented by a specific colour—just like an offender who can be identified by comparing his fingerprints with previous database entries. This produces a spatially resolved annotated image of the colon tissue section. Both PURE members, Professor Andrea Tannapfel, Director of the Pathology Institute at the RUB, and Professor Axel Mosig, Head of Bioinformatics at the Department of Biophysics, made the essential contributions in creating the database and the evaluation algorithm. By now, the evaluation programme will run on any commercial laptop.

A spectrum as a biochemical fingerprint: By applying Fourier transform infrared and Raman imaging the RUB team obtains a "spectral fingerprint". It reflects the momentary condition of the cell on the level of proteins. Comparison with a "reference card index" makes it possible to allocate a "fingerprint" to a matching "suspect", for example, a colon tumour. Credit: RUB, picture: Faculty of Biophysics

Comparison with conventional tumour detection methods

In order to test the sensitivity and specificity of spectral histopathology, the RUB team compared SHP with classical immunohistochemical methods, in which tumours are identified with the aid of fluorescent labels. "The results match perfectly. It demonstrates impressively that spectral histopathology is capable of determining changes in tissue composition with high sensitivity and in an automated fashion," says Prof Gerwert. In fact, sensitivity and specificity of the method exceed 95 per cent. By extending their method to include Raman imaging, the RUB team achieved a higher spatial resolution than they could with infrared imaging, however, at the cost of prolonged measurement time. "Both methods complement each other excellently," comments Klaus Gerwert. "Infrared spectroscopy gives you a rapid overview of the entire section. We can then analyse suspicious regions in more detail by applying Raman imaging." Raman analysis, for example, reveals altered nuclei which are characteristic of tumours.

Explore further: 'Fingerprinting' breakthrough offers improved brain tumour diagnosis

More information: Kallenbach-Thieltges, A. et al. (2013): Immunohistochemistry, histopathology and infrared spectral histopathology of colon cancer tissue sections, Journal of Biophotonics. DOI: 10.1002/jbio.201200132

Mavarani, L. et al. (2013): Spectral Histopathology of colon cancer tissue sections by Raman imaging with 532 nm excitation provides label free annotation of lymphocytes, erythrocytes and proliferating nuclei of cancer cells, Analyst. DOI: 10.1039/C3AN00370A

Related Stories

'Fingerprinting' breakthrough offers improved brain tumour diagnosis

September 21, 2012
(Medical Xpress)—UK scientists have made a breakthrough in a new method of brain tumour diagnosis, offering hope to tens of thousands of people.

New method to test breast lesions could better detect cancer, save money by reducing repeat biopsies

May 31, 2013
A newly developed, single-step Raman spectroscopy algorithm has the potential to simultaneously detect microcalcifications and enable diagnosis of the associated breast lesions with high precision, according to data published ...

New method for early detection of colon cancer

September 4, 2013
A new, highly sensitive method to detect genetic variations that initiate colon cancer could be readily used for noninvasive colon cancer screening, according to a study published in Cancer Prevention Research, a journal ...

A promising new method for the diagnosis of breast cancer

October 24, 2013
According to a study that has just been published, a novel mammography procedure developed at the Paul Scherrer Institute (PSI), in cooperation with the Certified Breast Centre of the Kantonsspital Baden and the industrial ...

Recommended for you

New approach attacks 'undruggable' cancers from the outside in

January 23, 2018
Cancer researchers have made great strides in developing targeted therapies that treat the specific genetic mutations underlying a patient's cancer. However, many of the most common cancer-causing genes are so central to ...

Study: Cells of three advanced cancers die with drug-like compounds that reverse chemo failure

January 23, 2018
Researchers at Southern Methodist University have discovered three drug-like compounds that successfully reverse chemotherapy failure in three of the most commonly aggressive cancers—ovarian, prostate and breast.

'Hijacker' drives cancer in some patients with high-risk neuroblastoma

January 23, 2018
Researchers have identified mechanisms that drive about 10 percent of high-risk neuroblastoma cases and have used a new approach to show how the cancer genome "hijacks" DNA that regulates other genes. The resulting insights ...

Enzyme inhibitor combined with chemotherapy delays glioblastoma growth

January 23, 2018
In animal experiments, a human-derived glioblastoma significantly regressed when treated with the combination of an experimental enzyme inhibitor and the standard glioblastoma chemotherapy drug, temozolomide.

Researchers identify a protein that keeps metastatic breast cancer cells dormant

January 23, 2018
A study headed by ICREA researcher Roger Gomis at the Institute for Research in Biomedicine (IRB Barcelona) has identified the genes involved in the latent asymptomatic state of breast cancer metastases. The work sheds light ...

Boosting cancer therapy with cross-dressed immune cells

January 22, 2018
Researchers at EPFL have created artificial molecules that can help the immune system to recognize and attack cancer tumors. The study is published in Nature Methods.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.