Which phase involves blood vessels forming within tumor cells?

The correct answer is associated with the growth phase, which is characterized by several critical processes that allow tumors to expand and thrive. One of the key features of this phase is angiogenesis, the process through which new blood vessels form from existing ones. This is essential for tumor growth, as tumors require a sufficient blood supply to deliver oxygen and nutrients, enabling their continuous growth and survival.

As tumors reach a certain size, they outgrow their existing blood supply. To sustain themselves, they secrete signaling molecules that stimulate the growth of new blood vessels, effectively establishing their own vascular network. This not only supports their growth but also can facilitate the potential for metastasis, as the newly formed vessels can allow cancer cells to enter the bloodstream and spread to other parts of the body.

In summary, the growth phase is critical as it involves angiogenesis, equipping tumors with a necessary supply of nutrients and oxygen, which underscores its significance in cancer development and progression.