What are the phases of tumorigenesis in order?

The correct sequence of phases of tumorigenesis is crucial for understanding how cancer develops, progresses, and ultimately spreads within an organism. The choice that outlines the phases as initiation, hyperplasia, dysplasia, in situ cancer, invasive cancer, and metastasis provides a logical progression that reflects the biological changes occurring in cells as they transform into malignant tumors.

Initiation marks the first stage where genetic damage occurs in a cell, which can predispose it to cancer development. Following initiation, hyperplasia represents an increase in the number of normal cells as they proliferate but maintain their normal architecture. Dysplasia follows, characterized by abnormal cell growth with alterations in size, shape, and organization, indicating a precancerous state.

As the process continues, the term in situ cancer refers to cancer that remains localized and has not yet invaded surrounding tissues. Once the cancer cells invade neighboring tissues, it is defined as invasive cancer. Finally, metastasis indicates the spread of cancer cells to distant sites in the body, leading to secondary tumors.

This ordered progression is critical for understanding how interventions might be applied at different stages of tumor development, making the sequence presented the most accurate reflection of the tumorigenesis process.