In foreign countries, like United States cancer is the second most cause of death, where 1.4 million cancer cases are diagnosied annually. One third of the members will develop some type of invasive cancer during their lifetime. In that proportion women have an approximately 1:7 lifetime chance of developing breast cancer and men have an approximately 1:5 chance of developing prostate cancer. Most of the cancers and their causes remains unknown for someone. In the recent stage, mutations in DNA sequences which leads to abnormal or unregulated expression of protoncogenes or deletion of tumor suppressor genes or both processes have been linked or connected to abnormal cellular proliferation. For cellular growth, oncogenes encode factor receptors, growth factors, or elements of the proliferative machinery of the cancer cell. Tumor suppressor genes govern regulatory proteins that normally suppress cellular proliferation.
Due to environmental exposure, genetic susceptibility, infectious agensts, and other factors this cancer results from these and other mutations. The chromosomal abnormalities such as inversions, translocations, duplications or deletions were exhibited in most of the tumours. Certain genetic alterations are strongly associated with specific malignancies although not in particular. The c-myc oncogene in burkitt's lymphoma is activated by translocation of genetic material from chromosome 8 to chromosome 14. The loss of the long arm of chromosome 18 predicts a poor outcome in colon cancer.
A tumour suppressor termed DCC which means deleted in colorectal cancer is thought to be inactivated by this loss. When compared with colorectal cancers that express DCC, deletion of DCC is associated with a 30% reduction in stage II cancers amd 20% in stage III in the 5-year survival rate.
Cancer occurs more in people after 50 or 60 years of age. In most of the older people around 80 years or above, some characteristics of cancer have been noted during life and after their death in post-martem studies of people suffering from cancers. 1. Lung and stomach cancer were seen in many cases, both in males and females. 2. In men, small microscopic cancers of the prostate were very common. 3. The type of adenocarcinoma, lung cancer was found often and was commoner in women than in men. 4. The growth in rate of cancers in general was slow. 5. The typs of cancers arising in different organs at the same was not an uncommon feature. 6. Lesions regarded as precursors to cancers were often observed in stomach, colon and lungs.
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Tags: origin of cancer, cancer books, origin cancer, the history of cancer, things that cause cancer, what can cause cancer, leading causes of cancer, causes pancreatic cancer, breast tumours, cancer stages
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