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Mysterious changes in tumor cells: What are the genetic mutations and development paths of squamous cell lung cancer?
Squamous cell lung cancer (SCC) is a histological type of non-small cell lung cancer (NSCLC) and the second most common type of lung cancer after lung adenocarcinoma. This cancer usually originates in the bronchi and the tumor cells have morphological characteristics similar to epidermal cells, with a squamous appearance.
Squamous cell lung cancer is strongly associated with tobacco smoking and is more common in the lungs than other types of non-small cell lung cancer.
Symptoms and signs
Symptoms of squamous cell lung cancer are similar to those of other forms of lung cancer and include a persistent cough, coughing up blood, chest pain, shortness of breath, and weight loss. These symptoms may result from local invasion or compression of nearby thoracic structures, such as affecting the esophagus and causing dysphagia, or compressing the laryngeal nerves and causing changes in the voice, or even compressing the superior vena cava and causing facial edema.
Causes and risk factors
Risk Factors
The occurrence of squamous cell lung cancer is closely related to smoking history. According to research, the relative risk of smokers compared to non-smokers is 5.5, while the risk rises to around 16 for those with a smoking history of more than 30 years, and can be as high as 22 for those with a smoking history of more than 40 years.
Mechanism and pathology
This cancer usually develops in the large bronchi and metastasizes in the early stages often affecting local regional lymph nodes, with delayed spread outside the chest. Therefore, the pathological changes and gene mutations of squamous cell lung cancer affect the development path of the tumor.
Gene mutation and copy number variation
Squamous cell lung cancer is one of the tumors with the highest number of mutations, mainly because smoking is a strong mutagenic factor.
In squamous cell lung carcinoma, many tumor suppressor genes have inactivating mutations, such as TP53 (81%), MLL2 (20%), CDKN2A (15%), KEAP1 (12%), and PTEN (8 %).
RNA expression characteristicsIn recent studies, four mRNA expression subtypes (primitive, basal, secretory, and classical) have been found to exist in squamous cell carcinoma. The original subtype is often associated with poor patient survival, which lays the foundation for the development of improved patient outcomes and personalized treatment.
Diagnosis and classification
Early-stage squamous cell lung cancer is mostly asymptomatic and is usually discovered incidentally during imaging studies. In advanced stages, the tumor can block the main airway, causing more obvious signs of disease.
Categories
According to the 2015 WHO classification of lung tumors, squamous cell lung cancer is divided into three types: keratinizing, non-keratinizing, and basal. There is no evidence of prognostic significance in these categories.
TreatmentTreatment for squamous cell lung cancer takes into account many factors, including the stage of the cancer, its resectability, the patient's overall health, and the genetic variations in the tumor. Early-stage squamous cell lung cancer is usually treated similarly to other types of non-small cell lung cancer. Surgery is the most common treatment, which may be followed by radiation therapy or chemotherapy.
EpidemiologyAccording to the survey, squamous cell lung cancer accounts for 22.6% of all lung cancer cases, and its incidence rate in men is generally higher than that in women. As the smoking rate decreases year by year, the relative incidence of squamous cell lung cancer has also decreased.
However, in the face of the development of squamous cell lung cancer, scientists are still exploring more effective treatment options and preventive measures. Will future research bring a deeper understanding and open up new treatment perspectives?
