Squamous cell carcinoma, also known as squamous carcinoma, is a malignant tumor that originates from the epidermis or skin appendages. It is commonly found in the skin, mouth or mucous membranes, and can also originate in the bronchi, renal pelvis and bladder. Histologically, cancer can be classified into three levels: grade I is highly differentiated cancer, which is less malignant; grade II is moderately differentiated cancer, which is moderately malignant; and grade III is poorly differentiated cancer, which is more malignant. It is a step-by-step process from normal cells, undifferentiated cells to hypodifferentiated cells to moderately differentiated to highly differentiated, and then to mature cells. Cancer can occur at any step in the whole process. Hypodifferentiated squamous carcinoma is a kind of squamous carcinoma formed at the early stage of differentiation, which is more malignant, has stronger invasive growth and metastasizes earlier, so it is more harmful to the organism and more dangerous to life.