Improved early diagnosis of breast cancer could be in sight thanks to researchers in the UK.

Calcium-containing structures within tissues can indicate the presence of cancer; those containing calcium oxalate usually indicate benign tumours, whilst calcium hydroxyapatite-containing ones can indicate malignancy. Mammography, used in breast cancer diagnosis, cannot accurately make a distinction between the structures because it detects morphology not chemical composition. This means that other methods are often used, such as needle biopsy. However, this procedure is invasive and only 10-25% of suspected cancer cases requiring needle biopsy turn out to be malignant.  

Now, Nicholas Stone, at the Gloucestershire Royal Hospital in Gloucester, and colleagues, have found a way of telling the structures apart using Raman spectroscopy.

Raman spectroscopy uses laser light to probe the molecular contents of tissues and cells from the outside, explained Stone. The signal that comes back from the tissue acts like a molecular fingerprint, he added, and so reveals chemical information about objects buried within the tissue. 

Until recently, it was possible to probe Raman spectra only from the first few 100?m of tissue. By improving the method, Stone and his colleagues have now extended this to depths of around 2mm in human breast tissue. Further work will involve extending this to at least 2cm, said Stone.

So far the technique has been used on human breast tissue in vitro, but work towards in vivo  measurements is in progress. John McGarvey, an expert in Raman spectroscopy at Queen's University Belfast, UK, said that the work is a step towards the 'development of a robust, spectroscopically-based probe, with ultimate diagnostic potential.'

Michael Smith