KLK6 and lung adenocarcinoma: Tracking KLK6 expression across the histopathological continuum of lung adenocarcinoma development—from pre-invasive in situ adenocarcinoma (AIS) to minimally invasive adenocarcinoma (MIA) and finally to invasive adenocarcinoma (IAC) by spatial transcriptomics—revealed a gradual increase in KLK6 expression that paralleled the advancement of malignant progression (Figure 11E), underscoring its potential role in driving tumor invasion and aggressiveness.