Cancer is the result of increased cell division, often following a mutation in DNA. Tumors have a multi-step development pathway that may or may not affect the surrounding tissue depending on whether it’s benign or malignant (CancerQuest). 

Benign tumors, like the occasional skin wart, stays within the area it initially grew, not posing a great threat to your immediate health.

However, malignant tumors are much more dangerous because they can invade the tissues surrounding it and travel throughout the body (this is termed as a “metastasized tumor”) (NCBI).

There are “initiators” that “initiate” tumor development by altering the DNA through mutations. For example, the correlation between smoking and lung cancer is linked to benzopyrene, which is an initiator of tumors. 

In addition, certain bacteria and viruses can initiate mutations in DNA, such as HPV. Once the DNA has been tampered with, it’s possible for the cell to proliferate without the barriers that stop normal cells from dividing. This is the “promotion” phase and there are non-mutagenic agents/”Promoters” that aid in proliferation such as mitogens, cytotoxins, and the inflammatory response (Potter).

The altered cells increase in number and start to look more abnormal compared to the original tissue. The organization of cells begins to fall apart here.

Neoplasms refer to "new growth."

Malignant neoplasms are officially cancerous and have invaded the outside tissue and/or metastasized to other areas by utilizing the bloodstream or lymph vessels.

However, there can also be benign neoplasms, which are benign (non-cancerous) tumors that have acquired mutations to proliferate but have not invaded surrounding tissues.