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

Reversion 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 reversion sequence were the red area in the diagram above, the DNA sequence after reversion would be the same length. However, since the orientation of the reverted DNA sequence is different, the coded amino acids in the protein will differ. If it is a piece of non-coding sequence and the reversed sequence does not start a transcription of a new gene, nothing happens. However, if it is a piece of non-coding sequence originally and the reversed sequence contains an initiation codon, or a new gene, such as one of the many oncogenes, it may be constitutively expressed. If the reversed sequence is encoding for a segment or domain of important amino acids, the reversion may change the function of the gene, including enhanced function, reduced function, non-function or altered function. If the reversed sequence is large, it may cause the malfunction of several genes.

"Solid tumor" cells grown from enriched cancer stem cells, CancerStemCell™, have all types of mutations, including reversions. It is not known what the reverted DNA sequences are, or how many reversions have occurred in one cancer cell or the heterogeneous population. However, the degree of mutations and number of antigens in enriched cancer stem cells are believed to be 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.