I think the tumor samples have two copies of the chromosomes. But for constitutional samples, do they only have one copy of the chromosomes?
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2$\begingroup$ Every cell has two copies of each chromosomes - except for sperm and egg cells. $\endgroup$ – Chris♦ Jun 7 '17 at 18:14
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2$\begingroup$ ...and some cancerous cells. $\endgroup$ – canadianer Jun 8 '17 at 5:16
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Constitutional samples do, as you surmised, refer to germ cells (sperm or ovum). Hence they have 1 copy of DNA instead of 2.
Tumours, as they acquire more mutations, often have aneuploidy, or different numbers of chromosomes, and can also have increased incidence of Xn chromosomes where X > 2. This is polyploidy for humans and organisms with normal 2n chromosomes.
