Based on the biological characteristics, treatment and prognosis of lung cancer, the World Health Organization (WHO) has divided it into two major categories: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). ) carcinoma. Adenocarcinoma is the most common type of lung cancer in the United States and the type with the highest incidence in nonsmoking patients. Gene expression profiling (using DNA microarrays) has identified subtypes of lung adenocarcinoma (i.e., bronchial, squamous, and large cell adenocarcinoma) that are associated with stage-specific survival and metastatic patterns. Bronchial adenocarcinoma was associated with prolonged survival in early stage lung cancer and squamous adenocarcinoma was associated with prolonged survival in advanced lung cancer. Certain prognostic factors may suggest survival in patients with NSCLC. Factors suggesting a good prognosis include early stage at diagnosis, good physical status (PS) (ECOG score 0, 1 or 2), no significant weight loss (no more than 5%) and female. Age and histological type are of little prognostic significance. A prognostic biomarker is a biomolecule that predicts patient survival (independent of the treatment received); that is, this biomolecule is an indicator of the inherent aggressiveness of the tumor. A prognostic biomarker is a biomolecule that predicts efficacy; i.e., there is an interaction between this biomolecule and treatment in terms of its impact on patient regression. Several biomarkers can be used as prognostic determinants and predictive markers of efficacy in NSCLC. Among these biomarkers, the evidence is strongest for the following markers: epidermal growth factor receptor (EGFR), 5′ nucleic acid endonuclease of the nucleotide shear repair complex (ERCC1), the proto-oncogene Kirsten-Rous sarcoma virus (K-ras), and the regulatory subunit of ribonucleotide reductase (RRM1). Biological prognostic factors including oncogene (p53) mutations, k-ras oncogene activation and other biological markers may be valuable in predicting poor prognosis. stage I lung adenocarcinoma patients with specific genetic abnormalities such as k-ras oncogene activation have poor prognosis and short disease-free survival. The presence of EGFR exon 19 deletion or exon 21 L858R mutation does not seem to determine the survival prognosis of NSCLC patients (independent of treatment). However, EGFR exon 19 deletion or exon 21 L858R mutation predicts benefit from treatment with EGFR-TKI. High levels of ERCC1 predicted better survival outcomes (independent of treatment) in NSCLC patients compared to low levels of ERCC1. K-ras mutations predicted ineffectiveness of platinum/vincristine chemotherapy or EGFR TKI therapy. High RRM1 expression predicted better survival outcomes in NSCLC patients compared to low RRM1 expression (independent of treatment). Meanwhile, high RRM1 expression predicted poorer outcomes with gemcitabine-based chemotherapy.