How are the chromosomes different in the cancer cells compared to normal cells? How could these differences lead to cancer?

Genomic Instability

Explanation:

Normal cells have normal DNA and a normal number of chromosomes. Cancer cells often have an abnormal number of chromosomes and the DNA becomes increasingly abnormal as it develops a multitude of mutations.In contrast to normal cells, cancer cells don't stop growing and dividing, this uncontrolled cell growth results in the formation of a tumor. Cancer cells have more genetic changes compared to normal cells, however not all changes cause cancer, they may be a result of it.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.