[Epithelial dysplasia of the digestive tract and flow cytometry]

The early diagnosis of digestive cancer is usually based on the detection of the presence epithelial histological abnormalities known as dysplasia. The histological features described constitute an intermediate step between normal tissue and actual cancer. Two degrees of dysplasia are now distinguished: moderate dysplasia and severe dysplasia (the latter being equivalent to in situ cancer or stage 0 cancer). The difficulty in reliably identifying and classifying dysplasia has led to the development of additional methods able to detect abnormalities of the genetic material, particularly of DNA. The use of flow cytometry to examine tissue makes it possible to analyse the DNA content of the tissue nucleus by nucleus. Normal tissues have a normal DNA content and are described as "diploid". Tumor tissues frequently contain abnormal quantities of DNA and are described as "aneuploid". Pre-cancerous aneuploidism could be identified before cancer develops and detected in dysplastic states. The authors report their own experience and that of many other authors of the value of this additional method of investigating precancerous lesions of the digestive tract.