Invasion and metastasis
The hallmark of a malignant tumor is its tendency to invade and infiltrate local and adjacent structures and, eventually, spread from the site of its origin to non-adjacent regional and distant sites in the body, a process called metastasis. If unchecked, tumor growth and metastasis eventually creates a tumor burden so great that the host succumbs. Carcinoma metastasizes through both the lymph nodes and the blood. Mutation
Whole genome sequencing has established the mutation frequency for whole human genomes. The mutation frequency in the whole genome between generations for humans (parent to child) is about 70 new mutations per generation.Carcinomas, however, have much higher mutation frequencies. The particular frequency depends on tissue type, whether a mis-match DNA repair deficiency is present, and exposure to DNA damaging agents such as components of tobacco smoke. Tuna and Amos have summarized the mutation frequencies per megabase (Mb) in some carcinomas, as shown in the table (along with the indicated frequencies of mutations per genome). Cause of mutations
The likely major underlying cause of mutations in carcinomas is DNA damage. For example, in the case of lung cancer, DNA damage is caused by agents in exogenous genotoxic tobacco smoke (e.g. acrolein, formaldehyde, acrylonitrile, 1,3-butadiene, acetaldehyde, ethylene oxide and isoprene). Endogenous (metabolically caused) DNA damage is also very frequent, occurring on average more than 60,000 times a day in the genomes of human cells. Externally and endogenously caused damages may be converted into mutations by inaccurate translesion synthesis or inaccurate DNA repair (e.g. by non-homologous end joining).
Epidemiology
While cancer is generally considered a disease of old age, children can also develop cancer. In contrast to adults, carcinomas are exceptionally rare in children. Less than 1% of carcinoma diagnoses are in children.The two biggest risk factors for ovarian carcinoma are age and family history. References


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