The factors used to determine tumor grade can vary between different types of cancer. Tumor grade is not the same as the stage of a cancer. Cancer stage refers to the size and/or extent (reach) of the original (primary) tumor and whether or not cancer cells have spread in the body. Cancer stage is based on factors such as the location of the primary tumor, tumor size, regional lymph node involvement (the spread of cancer to nearby lymph nodes), and the number of tumors present.
According to an international team of scientists reporting in the Proceedings of the National Academy of Sciences, an asteroid or comet that landed in what is now the Canadian province of Quebec might have led to a significant climate change event known as Younger Dryas.
What Causes Chagas? Chagas, or Trypanosoma cruzi, is a parasitic disease transmitted by an insect that lives in the walls and roofs of mud and straw housing, common in rural areas and urban slums in Latin America. The bugs that carry the disease, known as âtriatominesâ, emerge at night to feed.