"Researchers believe they have identified a molecule that could be key to preventing over-treatment of breast cancer by revealing when the early stage of the disease is likely to develop into its invasive form. Over-diagnosis and over-treatment has become a contentious issue, provoking impassioned argument between epidemiologists. Some have gone so far as to argue that the harm caused by needless diagnosis and damaging treatment for cancerous cells that would have gone away or never progressed to disease in the woman's lifetime outweighs the number of lives saved.. But the Breast Cancer Campaign says that a routine test could spare women the difficult decision on whether to have treatment after research funded by the charity found that the molecule alpha v beta 6 could tell doctors which cases of ductal carcinoma in situ (DCIS), a condition in which non-invasive cancerous cells are contained within the milk ducts of the breast, are most likely to develop into early invasive breast cancer. Study co-author Professor Louise Jones said: "You have a chance you can watch and monitor [where the molecule is not present]. "We often pick this [DCIS] up in screening, which means that women are 50 or older and if it takes 30 years for that disease to progress, watching and waiting might be a sensible way to go. It's difficult for women to accept that they might need to have a mastectomy for something that you don't know is going to harm them."