Emerging insights into STK11, KEAP1 and KRAS mutations: implications for immunotherapy in patients with advanced non-small cell lung cancer

Immune checkpoint inhibitors (ICIs) have become an established treatment option for patients with advanced non-small cell lung cancer (NSCLC). However, the efficacy of single-agent immunotherapy as well as in combination with chemotherapy seems to be dependent on the presence of molecular abnormalities in some genes-serine/threonine kinase 11 (STK11), Kelch-like ECH-associated protein 1 (KEAP1) and Kirsten rat sarcoma viral oncogene homolog (KRAS) among them. The KEAP1 gene is a critical regulator of the cellular response to oxidative stress and electrophilic stress, thus playing a pivotal role in maintaining cellular homeostasis. The STK11 gene encodes a serine/threonine kinase (STK11) involved the regulation of cell growth, polarity, motility, differentiation and cell metabolism. The STK11 gene mutations are often associated with an immunologically "cold" tumour microenvironment. The co-occurrence of STK11 or KEAP1 abnormalities with the KRAS mutation changes the composition of the tumour microenvironment as compared when presented alone. The current data, based on retrospective analyses of clinical trials, indicate that the co-existence of STK11 and KEAP1 genes mutations with the KRAS gene mutations have negative impact on the prognosis, regardless of treatment methods, in patients with advanced NSCLC. However, this group of patients should not be omitted because they constitute a significant percentage of advanced NSCLC patients. Immunotherapy focused on two ICIs [anti-programmed death 1 (PD-1)/anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4)] combined with chemotherapy, may be more effective than immunotherapy or chemotherapy alone in this group of patients. Confirmation of this thesis can be found in the results of available clinical studies. Here, we summarize the theoretical justification as well as the results of clinical trials for combining immunotherapy in patients with STK11-, KEAP1- and KRAS-mutated genes. There is certainly a need to create a prospective clinical trial to assess the effectiveness of combined immunotherapy in the discussed group of patients.