Interestingly, Meflin+ stromal cells were not observed in noninvasive tumors (adenocarcinoma in situ; AIS), whereas they were sparsely present in preinvasive lesions (PIL) with a lepidic growth, a pattern of noninvasive cell proliferation along preexisting alveolar wall, adjacent to invasive tumors (Figs 1A and S1). Here, ISLR is linked to adenocarcinoma in situ.