[11C]Erlotinib PET cannot detect acquired erlotinib resistance in NSCLC tumor xenografts in mice

PET Imaging of Lung Cancers in Precision Medicine: Current Landscape and Future Perspective

Despite the recent advances in cancer treatment, lung cancer remains the leading cause of cancer mortality worldwide. Immunotherapies using immune checkpoint inhibitors (ICIs) achieved substantial efficacy in nonsmall cell lung cancer (NSCLC). Currently, most ICIs are still a monoclonal antibody (mAb). Using mAbs or antibody derivatives labeled with radionuclide as the tracers, immunopositron emission tomography (immunoPET) possesses multiple advantages over traditional ¹⁸F-FDG PET in imaging lung cancers. ImmunoPET presents excellent potential in detecting, diagnosing, staging, risk stratification, treatment guidance, and recurrence monitoring of lung cancers. By using radiolabeled mAbs, immunoPET can visualize the biodistribution and uptake of ICIs, providing a noninvasive modality for patient stratification and response evaluation. Some novel targets and associated tracers for immunoPET have been discovered and investigated. This Review introduces the value of immunoPET in imaging lung cancers by summarizing both preclinical and clinical evidence. We also emphasize the value of immunoPET in optimizing immunotherapy in NSCLC. Lastly, immunoPET probes developed for imaging small cell lung cancer (SCLC) will also be discussed. Although the major focus is to summarize the immunoPET tracers for lung cancers, we also highlighted several small-molecule PET tracers to give readers a balanced view of the development status.

The Development of Positron Emission Tomography Tracers for In Vivo Targeting the Kinase Domain of the Epidermal Growth Factor Receptor

Multiple small molecule PET tracers have been developed for the imaging of the epidermal growth factor receptor (EGFR). These tracers target the tyrosine kinase (TK) domain of the receptor and have been used for both quantifying EGFR expression and to differentiate between EGFR mutational statuses. However, the approaches for in vivo evaluation of these tracers are diverse and have resulted in data that are hard to compare. In this review, we analyze the historical development of the in vivo evaluation approaches, starting from the first EGFR TK PET tracer [11C]PD153035 to tracers developed based on TK inhibitors used for the clinical treatment of mutated EGFR expressing non-small cell lung cancer like [11C]erlotinib and [18F]afatinib. The evaluation of each tracer has been compiled to allow for a comparison between studies and ultimately between tracers. The main challenges for each group of tracers are thereafter discussed. Finally, this review addresses the challenges that need to be overcome to be able to efficiently drive EGFR PET imaging forward.

Identifying nonsmall-cell lung tumours bearing the T790M EGFR TKI resistance mutation using PET imaging

Specific mutations significantly affect response to epidermal growth factor tyrosine kinase inhibitor (EGFR-TKI) treatment in lung cancer patients. Identifying patients with these mutations remains a major clinical challenge. EGFR T790M mutation, which conveys resistance to in the present study, [¹⁸ F]FEWZ was assessed in vitro to determine efficacy relative to the starting compound and in vivo to measure the biodistribution and specificity of binding to EGFR wild-type, L858R and T790M bearing tumours. [¹⁸ F]FEWZ is the first evidence of a radiolabeled third generation anilinopyrimidine-derived tyrosine kinase inhibitor targeting T790M mutation bearing tumours in vivo.

miR-767-3p Inhibits Growth and Migration of Lung Adenocarcinoma Cells by Regulating CLDN18

Claudin18 (CLDN18) is necessary for intercellular junctions and is reported to be involved in cell migration and metastasis, making it like an oncogene in various cancer types. However, the biological function and regulatory mechanisms of CLDN18 in lung adenocarcinoma are not yet clear. In this study, we found downregulation of miR-767-3p and upregulation of CLDN18 in lung adenocarcinoma tissue and cell lines. In addition, there was a negative correlation between the expression of miR-767-3p and CLDN18 in lung adenocarcinoma. Double luciferase reporter gene analysis showed that miR-767-3p modulates the expression of CLDN18 by binding its 3'-untranslated regions (3'-UTR). Knockdown of CLDN18 results in a decrease in the growth, migration, and invasion of lung adenocarcinoma cells. Although overexpression of miR-767-3p inhibits lung adenocarcinoma cell growth and migration, these effects can be rescued by reexpressing CLDN18. In summary, the data suggest that miR-767-3p inhibits tumor cell proliferation, migration, and invasion by targeting CLDN18, providing a promising therapeutic target for lung adenocarcinoma.