Is the common nature of cancer worldwide purely a man-made phenomenon? That is what some researchers now suggest. Scientists have only found one case of the disease in investigations of hundreds of Egyptian mummies, researcher Rosalie David at the University of Manchester in England said in a statement. The rarity of cancer in mummies suggests it was scarce in antiquity, and that cancer-causing factors are limited to societies affected by modern industrialization," researcher Michael Zimmerman at Villanova University in Pennsylvania said in a statement. "In an ancient society lacking surgical intervention, evidence of cancer should remain in all cases." Zimmerman was the first to diagnose cancer in an Egyptian mummy by analyzing its tissues on a microscopic level, identifying rectal cancer in an unnamed mummy who had lived in the Dakhleh Oasis during the Ptolemaic period 1,600 to 1,800 years ago. As they analyzed ancient literature, they did not find descriptions of operations for breast and other cancers until the 17th century, and the first reports in the scientific literature of distinctive tumors have only occurred in the past 200 years, such as scrotal cancer in chimney sweepers in 1775, nasal cancer in snuff users in 1761 and Hodgkin's disease in 1832. David and Zimmerman therefore argue that cancer nowadays is largely caused by man-made environmental factors such as pollution and diet. They detailed their findings in the October issue of the journal Nature Reviews Cancer.