One type of genetic mutation in enriched cancer stem cells is duplication.

Duplication of a block of DNA sequence may lead to various results, depending on how big the sequence is, where it is located and how important the coding sequence is. If the duplicated sequence were red in color in the diagram above, after duplication of the sequence, the block of DNA sequence would be longer. Duplicated DNA sequence may cause the malfunction of one to several different genes, including the over-expression of one gene and non-expression of another gene. If it is a piece of non-coding sequence and the duplicated sequence starts with a new starting code, a new gene, such as one of many oncogenes, may be expressed. The duplicated DNA sequence can be located at different places, making the mutations more complex.

"Solid tumor" cells grown from enriched cancer stem cells, CancerStemCell™, have all types of mutations, including duplications. It is not known what the duplicated DNA sequences are or how many duplications have occurred in any one cancer cell or the heterogeneous population. However, the degree of mutations and number of antigens in the "solid tumor" cells are comparable to that of metastasized tumor cells since the whole cell "giant liposome" cancer vaccines, CancerVaccine™, made out of "solid-tumors" grown from enriched cancer stem cells and metastasized tumor cells have induced similar immune responses.