LKB1/STK11 Expression in Lung Adenocarcinoma and Associations With Patterns of Recurrence

BACKGROUND: Mutations in the serine-threonine kinase LKB1/STK11 have been implicated in mediating resistance to checkpoint blockade among patients with advanced lung adenocarcinoma. We sought to examine the associations between clinicopathologic characteristics, tumor LKB1 expression, features of the immune microenvironment, and postoperative prognosis among patients with early-stage lung adenocarcinoma undergoing surgical therapy. METHODS: Formalin-fixed, paraffin-embedded specimens of patients undergoing resection of stage I-III, chemotherapy-naïve adenocarcinomas (1997–2008) were analyzed using tissue microarray sectioning. Sublobar resections were excluded. Intratumoral LKB1/STK11 expression was quantified as H-score. In a subset, tumor associated immune cell populations were quantified using whole tumor sections in peritumoral and intratumoral compartments. RESULTS: 104 patients met inclusion criteria. LKB1/STK11 expression (median H-score 102.9) was higher in women (median 123.3) than men (100.0, p=0.004) and in never-smokers (median 145.0) than former/current smokers (100.0, p=0.002). LKB1/STK11 expression was positively correlated with intratumoral infiltration of CD3(+) (r=0.351, P=0.005), CD4(+) (r=0.436, P