Evolution of immune escape mechanisms in the progression from preinvasive to invasive human lung adenocarcinoma

Abstract

31Statement of Significance: Using multiplexed IF, we compared the cellular composition and 32 activation state of the tumor immune microenvironment between pre/minimally invasive and frankly 33 invasive adenocarcinoma. We found a progressive increase in immunosuppressive mechanisms in 34 association with disease progression suggesting that Interception strategies should be specifically 35 tailored based on underlying immune escape mechanisms 36 37Abbreviations: TME, tumor microenvironment; LUAD, lung adenocarcinoma; p-NS, Pure non-38 solid; AIS, adenocarcinoma in-situ; MIA, minimally invasive adenocarcinoma; GZB, granzyme B; 39ROI, region of interest; CT, computer tomography; EGFR, EGF receptor; TMA, tumor 40 microenvironment. 42Running title: Evolution of immune escape mechanisms in lung adenocarcinoma 43Word count: Main text, 5560 words. 65screening purposes, has led to the detection of ground-glass or non-solid nodules that are not 66 visible on plain chest radiography. Non-solid nodules appear on CT scanning as hazy opacities 67 that do not obscure the underlying lung parenchyma or vasculature. In most instances, non-68 solid nodules less than 5 mm in size represent focal proliferative lesions known as atypical 69 alveolar hyperplasia that are considered the earliest progenitor lesions of invasive 70 adenocarcinoma of the lung. The majority of non-solid nodules, particularly those ≤ 3cm in size, 71 typically harbor adenocarcinoma in-situ (AIS) or minimally invasive adenocarcinoma (MIA) 72 where the invasive component is ≤ 5 mm or less. Interestingly, 10-20% contain adenocarcinoma 73 with an invasive component exceeding 5 mm suggestive of a more aggressive phenotype. 74Regardless, the precise biological behavior of these non-solid nodules remains unclear as many 75 remain unchanged in size and appearance for many years. However, approximately 20-40% of 76 these nodules grow or develop areas of increased CT density (a manifestation of more invasive 77 malignancy) within a four-year window (1). Why some of these nodules retain an indolent 78 behavior while others progress to invasive malignancy is unclear. This uncertainty commits 79 patients to frequent, repeat imaging, and in some cases potentially harmful biopsies. 80The critical role of the tumor microenvironment (TME) in tumorigenesis is well-recognized (2-5). 81The TME is predominantly composed of immune cells, fibroblasts and vasculature. There are a 82 number of non-mutually exclusive hypotheses for how the TME contributes to tumorigenesis, 83 one of which is "immunoediting" or "immune surveillance", a cancer cell-extrinsic mechanism 84 that is engaged once cell-intrinsic killing mechanisms (e.g., apoptosis) have failed to eliminate 85 individual transformed cells (6-8). The proposed temporal phases of cancer immune 86 surveillance describing the homeostasis between cancer cell killing and survival include: 87 elimination, equilibrium and escape (9). In the elimination phase, innate and adaptive immunity 88 eliminate cancer cells before a tumor can emer...