Histological Subtypes Of Lung Adenocarcinoma Research Articles

Abstract 7640: Prognostic significance of S100A16 expression in patients with resected lung adenocarcinoma

Abstract Background: Lung cancer is the leading cause of cancer death worldwide. Tumor recurrence is the most common cause of treatment failure after surgical resection. The S100 protein family is a multigenic group of cytoplasmic calcium-binding proteins. S100A16 has to be reported to be an independent prognostic indicator of poor overall survival in lung adenocarcinoma recently. However, the prognostic value of S100A16 in recurrence-free survival (RFS) in patients with resected lung adenocarcinoma has not been well demonstrated. The relationship between S100A16 expression and the histological subtypes of lung adenocarcinoma remained unknown. Methods: A total of 79 patients with resected lung adenocarcinoma were included in the study. S100A16 expression was determined by immunohistochemistry in tumor specimens. The prognostic value of S100A16 overexpression and its relationship with clinicopathological variables, including histology subtypes, were investigated. Results: S100A16 overexpression tended to be significantly associated with order age (P = 0.074). There was no significant association between S100A16 overexpression and predominant pattern group (lepidic/acinar/papillary vs. micropapillary/solid) (P = 0.447). Univariate analysis indicated that pathologic stage (II or III vs. I) (P = 0.001) and S100A16 overexpression (P = 0.005) were significant prognostic factors for worse recurrence-free survival (RFS). Predominant pattern group (lepidic/acinar/papillary vs. micropapillary/solid) (P = 0.064) tended to be a significant prognostic factor for worse RFS. In multivariate analysis, pathologic stage (II or III vs. I) (HR, 27.847; 95% CI, 4.173 to 185.831; P = 0.001), and S100A16 overexpression (HR, 21.740; 95% CI, 2.516 to 187.870; P = 0.005) were still significant prognostic factors for worse RFS. Conclusions: S100A16 overexpression was a significant prognostic factor for worse RFS in patients with resected lung adenocarcinoma. This information is useful to stratify high-risk patients of recurrence after resection of lung adenocarcinoma. Citation Format: Jung-Jyh Hung. Prognostic significance of S100A16 expression in patients with resected lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7640.

The prognosis, chemotherapy and immunotherapy efficacy of the SUMOylation pathway signature and the role of UBA2 in lung adenocarcinoma.

Lung adenocarcinoma (LUAD) is one of the most common malignant tumors worldwide. Small Ubiquitin-like Modifier (SUMO)-ylation plays a crucial role in tumorigenesis. However, the SUMOylation pathway landscape and its clinical implications in LUAD remain unclear. Here, we analyzed genes involved in the SUMOylation pathway in LUAD and constructed a SUMOylation pathway signature (SUMOPS) using the LASSO-Cox regression model, validated in independent cohorts. Our analysis revealed significant dysregulation of SUMOylation-related genes in LUAD, comprising of favorable or unfavorable prognostic factors. The SUMOPS model was associated with established molecular and histological subtypes of LUAD, highlighting its clinical relevance. The SUMOPS stratified LUAD patients into SUMOPS-high and SUMOPS-low subtypes with distinct survival outcomes and adjuvant chemotherapy responses. The SUMOPS-low subtype showed favorable responses to adjuvant chemotherapy. The correlations between SUMOPS scores and immune cell infiltration suggested that patients with the SUMOPS-high subtype exhibited favorable immune profiles for immune checkpoint inhibitor (ICI) treatment. Additionally, we identified UBA2 as a key SUMOylation-related gene with an increased expression and a poor prognosis in LUAD. Cell function experiment confirmed the role of UBA2 in promoting LUAD cell proliferation, invasion, and migration. These findings provide valuable insights into the SUMOylation pathway and its prognostic implications in LUAD, paving the way for personalized treatment strategies and the development of novel therapeutic targets.

Tumor immune microenvironment (TIME) analysis of stage I lung adenocarcinoma with micropapillary pattern.

e20510 Background: Micropapillary is one of the most aggressive histologic subtypes of lung adenocarcinoma, which is considered a poor prognostic marker. Comprehensive analysis of tumor immune microenvironment (TIME) features of micropapillary of early invasive lung adenocarcinoma may provide better insight and facilitate the development of novel strategies for early detection and intervention. Methods: A total of 15 patients who underwent anatomical resection and were pathologically diagnosed with stage I micropapillary adenocarcinomas were included in this study. Gene expression profiles (GEPs) of tumor immune-related 289 genes were analyzed using NanoString nCounter. Differentially expressed genes(DEGs), estimation of TIME cell infiltration, and TIME signatures between micropapillary and non-micropapillary were assessed. Results: The number of micropapillary and non-micropapillary patients was 5 and 10. The comparison revealed CD69, IL6, CXCL8, CXCL2, POLR2A and so on were significantly upregulated in the micropapillary group compared with the non-micropapillary group, while HLA-DPA1, IFIT2, and other seven genes were down-regulated in the micropapillary group. These DEGs were mostly enriched in “positive regulation of cytokine production”， “T cell activation”， “receptor ligand activity，” and “signaling receptor activator activity” pathways according to GO enrichment analysis. The results of the KEGG analysis revealed that genes were significantly enriched in “IL-17 signaling pathway”, “TNF signaling pathway”, “cytokine-cytokine receptor interaction”, and so on. Meanwhile, different immune infiltration of the two groups was analyzed. Totally, there was a better TIME cell infiltration in the micropapillary group compared with the non-micropapillary group. Especially, the score of DCs and mast cells was significantly higher in micropapillary group. However, TIME signature scores were similar in both groups. Conclusions: Our study demonstrated that the TIME between micropapillary and non-micropapillary of stage I lung adenocarcinoma was different. Increased mast cells explained poor prognosis in lung adenocarcinoma with micropapillary pattern. A high level of DCs infiltration indicated that micropapillary adenocarcinoma might benefit from immunotherapy.

99. Histopathologic Correlation Somatic Variants in Non Small Cell Lung Cancer with High Tumor Mutation Burden

<h3>Introduction</h3> High tumor mutation burden (TMB), having at least 10 mutations/megabase (mut/Mb), is reported to be as high as 42% of non small cell lung adenocarcinoma (LADC). Micropapillary adenocarcinoma is one of the most aggressive histologic subtypes of lung adenocarcinoma (LADC) and is often associated with a poor prognosis. <h3>Methods</h3> We performed next-generation sequencing (NGS) with and explored histologic and molecular features in 33 consecutive TMB High LADC utilizing the Ion Oncomine Comprehensive Panel Plus (OCAPlus). <h3>Results</h3> LADC with high tumor mutation burdens (TMBs) were more likely to display necrosis, as well as papillary and aggressive micropapillary features. Interestingly, RBM10 truncations were enriched in aggressive TMB LACD, seen in 2/2 cases of pleomorphic carcinoma and 4/7 cases with papillary or micropapillary features. BRAF class 2 mutations (non V600E) were also more likely to be seen in these aggressive tumors, identified in 5/33 cases of TMB high LADC, while no class 1 BRAF V600E mutations were observed. <h3>Conclusions</h3> A subset of high TMB LADC is especially aggressive, with histology including necrosis, micropapillary, and pleomorphic features. A subset of these tumors, with an especially poor overall survival rate contain either class 2 BRAF variants or truncated RBM10 mutations in 7/10 cases identified with these aggressive histologic features.

A predictive model based on ground glass nodule features via high-resolution CT for identifying invasiveness of lung adenocarcinoma.

ObjectiveThe morphology of ground-glass nodule (GGN) under high-resolution computed tomography (HRCT) has been suggested to indicate different histological subtypes of lung adenocarcinoma (LUAD); however, existing studies only include the limited number of GGN characteristics, which lacks a systematic model for predicting invasive LUAD. This study aimed to construct a predictive model based on GGN features under HRCT for LUAD.MethodsA total of 301 surgical LUAD patients with HRCT-confirmed GGN were enrolled, and their GGN-related features were assessed by 2 individual radiologists. The pathological diagnosis of the invasive LUAD was established by pathologic examination following surgery (including 171 invasive and 130 non-invasive LUAD patients).ResultsGGN features including shorter distance from pleura, larger diameter, area and mean CT attenuation, more heterogeneous uniformity of density, irregular shape, coarse margin, not defined nodule-lung interface, spiculation, pleural indentation, air bronchogram, vacuole sign, vessel changes, lobulation were observed in invasive LUAD patients compared with non-invasive LUAD patients. After adjustment by multivariate logistic regression model, GGN diameter (OR = 1.490, 95% CI, 1.326–1.674), mean CT attenuation (OR = 1.007, 95% CI, 1.004–1.011) and heterogeneous uniformity of density (OR = 3.009, 95% CI, 1.485–6.094) were independent risk factors for invasive LUAD. In addition, a predictive model integrating these three independent GGN features was established (named as invasion of lung adenocarcinoma by GGN features (ILAG)), and receiver-operating characteristic curve illustrated that the ILAG model presented good predictive value for invasive LUAD (AUC: 0.919, 95% CI, 0.889–0.949).ConclusionsILAG predictive model integrating GGN diameter, mean CT attenuation and heterogeneous uniformity of density via HRCT shows great potential for early estimation of LUAD invasiveness.

The correlation between metabolic parameters in (18)F-FDG PET-CT and solid and micropapillary histological subtypes in lung adenocarcinoma

Objective: Solid and micropapillary pattern are highly invasive histologic subtypes in lung adenocarcinoma and are associated with poor prognosis while the biopsy sample is not enough for the accurate histological diagnosis. This study aims to assess the correlation and predictive efficacy between metabolic parameters in (18)F-fluorodeoxy glucose positron emission tomography/computed tomography ((18)F-FDG PET-CT), including the maximum SUV (SUV(max)), metabolic tumor volume (MTV), total lesion glycolysis (TLG) and solid and micropapillary histological subtypes in lung adenocarcinoma. Methods: A total of 145 resected lung adenocarcinomas were included. The clinical data and preoperative (18)F-FDG PET-CT data were retrospectively analyzed. Mann-Whitney U test was used for the comparison of the metabolic parameters between solid and micropapillary subtype group and other subtypes group. Receiver operating characteristic (ROC) curve and areas under curve (AUC) were used for evaluating the prediction efficacy of metabolic parameters for solid or micropapillary patterns. Univariate and multivariate analyses were conducted to determine the prediction factors of the presence of solid or micropapillary subtypes. Results: Median SUV(max) and TLG in solid and papillary predominant subtypes group (15.07 and 34.98, respectively) were significantly higher than those in other subtypes predominant group (6.03 and 10.16, respectively, P<0.05). ROC curve revealed that SUV(max) and TLG had good efficacy for prediction of solid and micropapillary predominant subtypes [AUC=0.811(95% CI: 0.715~0.907) and 0.725(95% CI: 0.610~0.840), P<0.05]. Median SUV(max) and TLG in lung adenocarcinoma with the solid or micropapillary patterns (11.58 and 22.81, respectively) were significantly higher than those in tumors without solid and micropapillary patterns (4.27 and 6.33, respectively, P<0.05). ROC curve revealed that SUV(max) and TLG had good efficacy for predicting the presence of solid or micropapillary patterns [AUC=0.757(95% CI: 0.679~0.834) and 0.681(95% CI: 0.595~0.768), P<0.005]. Multivariate logistic analysis showed that the clinical stage (Stage Ⅲ-Ⅳ), SUV(max) ≥10.27 and TLG≥7.12 were the independent predictive factors of the presence of solid or micropapillary patterns (P<0.05). Conclusions: Preoperative SUV(max) and TLG of lung adenocarcinoma have good prediction efficacy for the presence of solid or micropapillary patterns, especially for the solid and micropapillary predominant subtypes and are independent factors of the presence of solid or micropapillary patterns.

Correlation of Epidermal Growth Factor Receptor Mutation With Major Histologic Subtype of Lung Adenocarcinoma According to IASLC/ATS/ERS Classification.

ObjectiveOur prospective study aims to define the correlation of EGFR(epidermal growth factor receptor) mutations with major histological subtypes of lung adenocarcinoma from resected and non-resected specimens, according to the WHO 2015 classification, in Moroccan North East Population.MethodsEpidermal growth factor receptor mutations of 150 primary lung adenocarcinoma were performed using Real-Time PCR or SANGER sequencing. SPSS 21 was used to assess the relationship between histological subtypes of lung adenocarcinoma and EGFR mutation status.Results25 mutations were detected in the series of 150 lung adenocarcinomas, most of which were found in cases with papillary, acinar, patterns than without these patterns and more frequently occurred in the cases without solid pattern than with this pattern. A significant correlation was observed between EGFR mutation and acinar (P = 0,024), papillary pattern (P = 0,003) and, negative association with a solid pattern (P < 0,001). In females, EGFR mutations were significantly correlated with the acinar pattern (P = 0,02), whereas in males with the papillary pattern (P = 0,01). Association between the histologic component and exon 19 deletions and exon 21 mutations were also evaluated and, we found a significant correlation between the papillary major pattern with exon 19 mutations (P = 0,004) and, ex21 with the acinar component (P = 0,03).ConclusionAn analysis of resected and non-resected lung ADC specimens in 150 Moroccan Northeast patients, revealed that acinar and papillary patterns may predict the presence of a mutation in the EGFR gene. While the solid major pattern may indicate a low mutation rate of the EGFR gene.

Pre-operative Prediction of Ki-67 Expression in Various Histological Subtypes of Lung Adenocarcinoma Based on CT Radiomic Features.

Purpose: The aims of this study were to combine CT images with Ki-67 expression to distinguish various subtypes of lung adenocarcinoma and to pre-operatively predict the Ki-67 expression level based on CT radiomic features.Methods: Data from 215 patients with 237 pathologically proven lung adenocarcinoma lesions who underwent CT and immunohistochemical Ki-67 from January 2019 to April 2021 were retrospectively analyzed. The receiver operating curve (ROC) identified the Ki-67 cut-off value for differentiating subtypes of lung adenocarcinoma. A chi-square test or t-test analyzed the differences in the CT images between the negative expression group (n = 132) and the positive expression group (n = 105), and then the risk factors affecting the expression level of Ki-67 were evaluated. Patients were randomly divided into a training dataset (n = 165) and a validation dataset (n = 72) in a ratio of 7:3. A total of 1,316 quantitative radiomic features were extracted from the Analysis Kinetics (A.K.) software. Radiomic feature selection and radiomic classifier were generated through a least absolute shrinkage and selection operator (LASSO) regression and logistic regression analysis model. The predictive capacity of the radiomic classifiers for the Ki-67 levels was investigated through the ROC curves in the training and testing groups.Results: The cut-off value of the Ki-67 to distinguish subtypes of lung adenocarcinoma was 5%. A comparison of clinical data and imaging features between the two groups showed that histopathological subtypes and air bronchograms could be used as risk factors to evaluate the expression of Ki-67 in lung adenocarcinoma (p = 0.005, p = 0.045, respectively). Through radiomic feature selection, eight top-class features constructed the radiomic model to pre-operatively predict the expression of Ki-67, and the area under the ROC curves of the training group and the testing group were 0.871 and 0.8, respectively.Conclusion: Ki-67 expression level with a cut-off value of 5% could be used to differentiate non-invasive lung adenocarcinomas from invasive lung adenocarcinomas. It is feasible and reliable to pre-operatively predict the expression level of Ki-67 in lung adenocarcinomas based on CT radiomic features, as a non-invasive biomarker to predict the degree of malignant invasion of lung adenocarcinoma, and to evaluate the prognosis of the tumor.

Histopathologic features from preoperative biopsies to predict spread through air spaces in early-stage lung adenocarcinoma: a retrospective study

BackgroundAlthough spread through air spaces (STAS) is a robust biomarker in surgically resected lung cancer, its application to biopsies is challenging. Moreover, limited resection is not an effective treatment for STAS-positive lung adenocarcinoma. This study aimed to identify histologic features from preoperative percutaneous transthoracic needle biopsies (PTNBs) to predict STAS status in the subsequently resected specimens, and thus help in selecting the surgical extent.MethodsBetween January 2014 and December 2015, 111 PTNB specimens and subsequent resection specimens from consecutive lung adenocarcinoma patients were retrospectively examined. Histopathologic features of PTNB specimens and presence of STAS in subsequent resection specimens were evaluated and correlations between them were analyzed statistically.ResultsThe study participants had a mean age of 59 years (range, 35–81) and included 50 men and 61 women. Thirty-six patients were positive for STAS whereas 75 were negative. The micropapillary/solid histologic subtypes of lung adenocarcinoma (26 of 39; 66.7%; P < 0.001), necrotic/tumor debris (31 of 42; 73.8%; P < 0.001), intratumoral budding (ITB) (20 of 33; 60.6%; P < 0.001), desmoplasia (35 of 41; 85.4%; P < 0.001), and grade 3 nuclei (12 of 14; 85.7%; P < 0.001) were more common in STAS-positive tumors. Micropapillary/solid histologic subtype (OR, 1.35; 95% CI: 1.06, 1.67), ITB (OR, 1.64; 95% CI: 1.09, 2.83), desmoplasia (OR, 1.83; 95% CI: 1.36, 3.12), and N stage (N1 stage: OR, 1.37; 95% CI: 1.19, 1.87) (N2 stage: OR, 1.29; 95% CI: 1.07, 1.73) were independent predictors of STAS.ConclusionsMicropapillary/solid histologic subtype, ITB, and desmoplasia in preoperative PTNB specimens were independently associated with STAS in the subsequent resection specimens. Therefore, these can predict STAS and may help to optimize therapeutic planning.

Integrated Analysis of Genomic and Immunological Features in Lung Adenocarcinoma With Micropapillary Component.

BackgroundMicropapillary adenocarcinoma is one of the most aggressive histologic subtypes of lung adenocarcinoma (LADC), and even a minor proportion of micropapillary component (MPC) within the LADC could contribute to poor prognosis. Comprehensive analysis of genetic and immunological features of LADC with different percentages of MPC would help better understand cancer biology of this LADC subtype and direct future treatments.MethodsWe performed next-generation sequencing (NGS) for a discovery cohort of 43 LADC patients whose tumors were micro-dissected to separate MPC and non-MPC lesions and a reference cohort of 113 LADC patients. MPC-enriched genetic alterations that were detected in the discovery cohort were then confirmed using a validation cohort of 183 LADC patients. Immunological staining was also conducted on the MPC-containing samples in the discovery cohort.ResultsTumors with a higher percentage of MPC tended to harbor more tumor mutation burdens (TMBs) and chromosome instability (CIN). Some rare genetic events may serve as the genetic landscape to drive micropapillary tumor progression. Specifically, alterations in transcription termination factor 1 (TTF1), brain-specific angiogenesis inhibitor 3 (BAI3), mammalian target of rapamycin (MTOR), and cyclin-dependent kinase inhibitor 2A (CDKN2A) were cross-validated to be enriched in MPC-contained LADC. Additionally, tumors with a higher percentage of MPC were associated with a higher percentage of CD4+, CD8+, and PD-L1+ staining, and some genetic changes that were enriched in MPC, including MET amplification and MTOR mutation, were correlated with increased PD-L1 expression.ConclusionWe identified multiple novel MPC-enriched genetic changes that could help us understand the nature of this aggressive cancer subtype. High MPC tumors tended to have elevated levels of TMBs, T cell infiltration, and immunosuppression than low MPC tumors, implying the potential link between MPC content and sensitivity to immunotherapy.

Spatial distribution of immune checkpoint proteins in histological subtypes of lung adenocarcinoma

The most prevalent histological type of non-small cell lung cancer (NSCLC) is adenocarcinoma. The WHO classifies this tumor into subtypes according to the predominant growth pattern such as lepidic, acinar, papillary, solid or micropapillary, each harboring specific molecular features. NSCLC adenocarcinoma heterogeneity is discussed to be a reason for therapy failure using targeted therapy or immune checkpoint inhibitors. For successful therapy of immune checkpoint inhibitors the expression and distribution of the involved immune checkpoint proteins is essential. Therefore, we aimed to investigate the distribution of five prominent immune checkpoint proteins in regard of the histological growth patterns of lung adenocarcinoma. We performed immunohistochemical staining of 84 tumor segments from 22 resected tumor samples to evaluate the expression of PD-L1, PD-1, Nectin-2, PVR, and TIGIT in distinct growth patterns of lung adenocarcinoma. We determined a distinct heterogeneity between and within different tumor segments regarding morphological growth patterns. Furthermore, expression of immune checkpoint proteins varied between different growth pattern areas as well as within one distinct growth pattern. Expression of PVR was significantly higher in solid compared to acinar growth pattern (p= 0.00736). Of note, we detected TIGIT not only on tumor infiltrating lymphocytes but also on tumor cells, whereas non-neoplastic lung tissue was consistently TIGIT-negative. The immune checkpoint protein distribution in histologic subtypes of pulmonary adenocarcinoma displays an considerable intra- and intertumoral heterogeneity implying the requirement of either a multiregion or an adjusted analysis when determining the expression status of PD-1:PD-L1 and the TIGIT:PVR/Nectin-2 checkpoint proteins as predictive markers.

Tumor cell proliferation (Ki-67) expression and its prognostic significance in histological subtypes of lung adenocarcinoma

ObjectivesKi-67 is a key molecular marker to indicate the proliferative activity of tumor cells in lung cancer. However, Ki-67 expression and its prognostic significance in histological subtypes of lung adenocarcinoma (LUAD) remain unclear. Materials and MethodsWe retrospectively analyzed 1028 invasive LUAD patients who underwent surgery treatment between January 2012 and April 2020 in our department. Associations between Ki-67 expression and histological subtypes of LUAD, as well as other clinicopathological characteristics, were evaluated. The prognostic role of Ki-67 in LUAD subtypes was further assessed using log-rank test and univariate/multivariate Cox proportional hazards regression analyses. ResultsKi-67 expression differed across LUAD histological subtypes. The solid-predominant adenocarcinoma (SPA, 46.31 ± 24.72) had the highest expression level of Ki-67, followed by micropapillary (MPA, 31.71 ± 18.14), papillary (PPA, 22.09 ± 19.61), acinar (APA, 19.73 ± 18.71) and lepidic-predominant adenocarcinoma (LPA, 9.86 ± 8.10, P < 0.001). Tumors with solid or micropapillary components also had a higher Ki-67 expression than those without solid or micropapillary components. Besides, males, smokers, larger tumor size, lymph node metastasis and EGFR wild type were correlated with elevated Ki-67 expression. Univariate analysis indicated that increased Ki-67 expression and MPA/SPA subtypes were significantly associated with a poorer prognosis. Notably, the survival differences between LUAD subtypes vanished after adjusting for tumor size and Ki-67 expression in multivariate analysis, while Ki-67 was an independent prognostic factor of LUAD. Patients with MPA/SPA had non-inferior overall and disease-free survival than LPA/APA/PPA patients with a Ki-67 expression comparable to MPA/SPA subjects. ConclusionKi-67 expression varied considerably according to the predominant histological subtypes of LUAD. Ki-67 expression level and tumor size contributed to the survival differences between LUAD histological subtypes.

Diagnostic and therapeutic ERβ, HER2, BRCA biomakers in the histological subtypes of lung adenocarcinoma according to the IASLC/ATS/ERS classification

Several studies revealed that non–small cell lung cancers (NSCLCs) frequently express ER, PR, HER2 and carry BRCA mutation. However, these markers in histological subtypes of lung adenocarcinoma have not been thoroughly investigated. We retrospectively evaluated a total of 640 lung adenocarcinoma samples for ERα, ERβ, PR and HER2 expression by immunohistochemistry and western-blotting, for EGFR and BRCA mutation by real-time PCR and sequencing. Furthermore, HER2 amplification and mutation were explored in samples harboring immunopositivity HER2 using fluorescence in situ hybridization and real-time PCR, respectively. The micropapillary and invasive mucinous predominant adenocarcinoma were frequently detected the higher level of cytoplasmic ERβ (64.9% and 56.6%), HER2 (68.1% and 60.1%) protein expression. But, amplification of HER2 was detected in only three cases (3/110, 2.7%) and 26 HER2 mutations in 110 cases were identified (23.6%) in the HER2 immunopositivity patients. Logistic regression analysis showed that cytoplasmic ERβ (P = 0.032) and HER2 (P = 0.015) expression were independently associated with EGFR mutation. 8 patients (8/640, 1.25%) harbored pathogenic BRCA mutations, 6 with germline BRCA mutations and 2 with somatic BRCA1 mutations were detected with lacking ERβ, PR and HER2 expression. Acinar predominant adenocarcinoma had the higher percentage of BRCA mutations than other subtypes. A systematic examination of ERβ, HER2 and BRCA biomarkers could potentially be useful to diagnosis and identify patients with the histological subtypes of lung adenocarcinoma, who might benefit from the further individualized treatment of anti-hormone, anti-HER2 and/or PARP inhibitors therapeutics.

The expression of trefoil factor 3 is related to histologic subtypes and invasiveness in lung adenocarcinoma.

Adenocarcinoma is the most common histological type of lung cancer and has various histologic subtypes, including lepidic, papillary, acinar and invasive mucinous adenocarcinoma. Histologic subtypes are associated with tumor invasiveness. For example, the lepidic subtype is less invasive than the papillary/acinar subtype. Trefoil factor 3 (TFF3) is a small secreting protein that is a member of the trefoil factor family, which is involved in mucosal stabilization and repair through its mitogenic and antiapoptotic activities. TFF3 overexpression is associated with various types of cancer. In lung cancer, TFF3 is expressed significantly in adenocarcinoma. However, the relationship between TFF3 expression and histologic subtypes in lung adenocarcinoma is unclear. The current study immunohistochemically revealed that, beside invasive mucinous carcinoma, the expression of TFF3 in papillary and acinar adenocarcinoma was significantly higher than that in lepidic adenocarcinoma. To further confirm these results, the expression of TFF3 in cases with both lepidic and papillary/acinar areas were examined. The expression of TFF3 in papillary/acinar areas was significantly higher when compared with lepidic areas in a single sample. Furthermore, using the lung adenocarcinoma cell line A549, TFF3-knockdown cells were generated. The results revealed that knockdown of TFF3 attenuated invasion. In vitro and immunohistochemical assays using clinical samples demonstrated that TFF3 expression was associated with lung adenocarcinoma invasiveness. To the best of our knowledge, the current study is the first to report that TFF3 expression was associated with the histologic subtypes of lung adenocarcinoma.

Differences in PET/CT standardized uptake values involvement and survival compared to histologic subtypes of lung adenocarcinoma.

Lung adenocarcinoma is histologically diverse but has distinct histologic growth patterns. There is no consensus on the clinical benefit of this histologic model. We aimed to evaluate the differences in the distribution of the preoperative primary tumor positron emission tomography (PET)/computed tomography (CT) standardized uptake values (SUVs) and survival in the lung adenocarcinoma subtypes. We retrospectively evaluated the data of 107 patients with resected lung adenocarcinoma who had preoperative PET/CT between 2005 and 2017 in a single center. Patients had lepidic, acinar, papillary, micropapillary, and solid histologic subtypes. We compared fluorodeoxyglucose SUVs and survival data of histologic subtypes. The median age of the patients was 62 years (40-75), 76.4% were male, the median SUVmax was 9.4 (1-36.7), and the median follow-up time was 29 months (3-135 months). The median overall survival (OS) was 71 months and the median progression-free survival (PFS) was 33 months. SUVmax was significantly different in histologic subtypes: values for papillary, micropapillary, solid, acinar, and lepidic subtypes were 9.7, 8, 12, 9.1, and 3.9, respectively (p = 0.000). Solid predominant adenocarcinoma had significantly higher SUVmax than the other subtypes (p = 0.001). Lepidic predominant adenocarcinoma had significantly lower SUVmax than the other subtypes (p = 0.000). There was no significant difference in OS between histologic subtypes (p = 0.66), but PFS was significantly different between the groups (p = 0.017), and the solid subtype had a shorter PFS than the other histologic subtypes. Lung adenocarcinoma consists of a diverse group of diseases. Different SUVmax values are seen in different histologic subtypes of nonmetastatic lung adenocarcinoma. Solid predominant types have high SUVmax values while lepidic predominant types have lower SUVmax values. The solid subtype had a shorter PFS than the other histologic subtypes.

The Underlying Tumor Genomics of Predominant Histologic Subtypes in Lung Adenocarcinoma.

The purpose of the study is to genomically characterize the biology and related therapeutic opportunities of prognostically important predominant histologic subtypes in lung adenocarcinoma (LUAD). We identified 604 patients with stage I to III LUAD who underwent complete resection and targeted next-generation sequencing using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets platform. Tumors were classified according to predominant histologic subtype and grouped by architectural grade (lepidic [LEP], acinar or papillary [ACI/PAP], and micropapillary or solid [MIP/SOL]). Associations among clinicopathologic factors, genomic features, mutational signatures, and recurrence were evaluated within subtypes and, when appropriate, quantified using competing-risks regression, with adjustment for pathologic stage and extent of resection. MIP/SOL tumors had higher tumor mutational burden (p < 0.001), fraction of genome altered (p= 0.001), copy number amplifications (p= 0.021), rate of whole-genome doubling (p= 0.008), and number of oncogenic pathways altered ( p < 0.001) as compared with LEP and ACI/PAP tumors. Across all tumors, mutational signatures attributed to APOBEC activity were associated with the highest risk of postresection recurrence: SBS2 (p= 0.021) and SBS13 (p= 0.005). Three oncogenic pathways (p53, Wnt, Myc) were altered with statistical significance in MIP/SOL tumors. Compared with LEP and ACI/PAP tumors, MIP/SOL tumors had a higher frequency of targetable BRAF-V600E mutations (p= 0.046). Among ACI/PAP tumors, alterations in the cell cycle (p < 0.001) and PI3K (p= 0.002) pathways were associated with recurrence; among MIP/SOL tumors, only PI3K alterations were associated with recurrence (p= 0.049). These results provide the first in-depth assessment of tumor genomic profiling of predominant LUAD histologic subtypes, their associations with recurrence, and their correlation with targetable driver alterations in patients with surgically resected LUAD.

High tumor mutation burden predicts favorable outcome among patients with aggressive histological subtypes of lung adenocarcinoma: A population-based single-institution study

ObjectivesTumor mutation burden (TMB) is an emerging predictive cancer biomarker. Few studies have addressed the prognostic role of TMB in non-small cell lung carcinoma, with conflicting results. Moreover, the association of TMB with different histological subtypes of lung adenocarcinoma has hitherto not been systematically evaluated. Here we studied the prognostic value of TMB and its distribution in different histological subtypes of lung adenocarcinomas in a retrospective cohort using the most recent updated classification guidelines. Materials and methods176 surgically resected stage I–IV lung adenocarcinomas were histologically reclassified according to WHO 2015 guidelines. A modified classification subdividing the acinar subtype into classic acinar, complex glandular and cribriform subtypes was further applied and potentially prognostic histopathological characteristics such as tumor-infiltrating lymphocytes were evaluated. 148 patients with stage I–III tumors and complete follow-up data were included in the survival analyses. TMB was determined by a commercial next generation sequencing panel from 131 tumors, out of which 105 had survival data available. ResultsPredominant micropapillary, solid and complex glandular as well as nonpredominant cribriform histological subtypes were associated with significantly shorter survival. High TMB concentrated in micropapillary, solid and acinar predominant subtypes. Interestingly, TMB ≥ 14 mutations/MB conferred a stage- and histology-independent survival benefit compared to TMB < 14 in multivariable analysis for overall (HR 0.284, 95% CI 0.14–0.59, P=0.001) and disease-specific survival (HR 0.213, 95% CI 0.08–0.56, P=0.002). ConclusionTMB was an independent biomarker of favorable prognosis in our cohort of lung adenocarcinoma despite being associated with predominant histological subtypes considered aggressive.

Characterizing the molecular and immunological features of lung micropapillary adenocarcinoma.

e21036 Background: Micropapillary adenocarcinoma (MPC) is one of the most aggressive histologic subtypes of lung adenocarcinoma (ADC). Although the incidence of MPC predominant ADC is low, nearly half of ADCs contain a minor proportion of MPC, which could contribute to poor prognosis in these patients. Comprehensive analysis of genetic and immunological features of ADC with different MPC contents would help better understand cancer biology of this ADC subtype and direct future treatments. Methods: We performed panel next-generation sequencing (NGS) of 425 cancer-related genes for a discovery cohort of 43 ADC patients whose tumors were microdissected to separate MPC and non-MPC regions and a reference cohort of 113 ADC patients with unknown ADC histologic subtypes. MPC-enriched mutations were identified by comparing tumors with different original MPC contents within these cohorts, which was then confirmed using a validation cohort of 183 ADC patients. Staining of immunological markers was also conducted for MPC samples from the discovery cohort to investigate their tumor microenvironment. Results: We found that ADC tumors with higher MPC contents/similarities tended to harbor more tumor mutation burdens (TMBs) and chromosome instability (CIN). In addition, genetic alterations in transcription termination factor 1 ( TTF1), brain-specific angiogenesis inhibitor 3 ( BAI3), mammalian target of rapamycin ( MTOR), cyclin-dependent kinase inhibitor 2A ( CDKN2A), and CDKN2A were found to be enriched in MPC using the discovery and reference cohorts, which could then be cross-validated using the validation cohort. Tumors with higher MPC content were associated with elevated infiltration of CD4+, CD8+ and FOXP3+ T cells, especially at the peritumor regions. Higher percentage of PD-L1+ tumor cells were also found to be correlated with higher MPC content, suggesting of more immunosuppression in MPC predominant tumors than low MPC tumors. Conclusions: We identified multiple novel MPC-enriched genetic changes that could help understand the nature of MPC. MPC predominant tumors tended to have higher levels of TMBs, T cell infiltration, and immunosuppression than low MPC tumors, making it a potential candidate for immunotherapy, especially the combination therapy of anti-PD-1/PD-L1 drugs and anti-CTLA-4 drugs, which could inhibit PD-1/PD-L1 pathway and FOXP3+ Treg cells simultaneously.

Targeted sequencing analysis of predominant histological subtypes in resected stage I invasive lung adenocarcinoma.

e21067 Background: Lung adenocarcinoma (LADC) is classified into 5 main histological subtypes with distinct clinicopathologic characteristics: lepidic-predominant adenocarcinoma (LPA), acinar-predominant adenocarcinoma (APA), papillary-predominant adenocarcinoma (PPA), micropapillary component (MPC) and solid-predominant adenocarcinoma (SPA). However, the mutational profiles of predominant histological subtypes have not been well defined. In this study, we aimed to reveal the genomic landscape of the 5 main histological subtypes. Methods: Surgically resected tumor samples were obtained from 86 patients with pathological stage I invasive lung adenocarcinoma who underwent surgery between January 2015 and December 2018. No patient had received preoperative chemotherapy or radiotherapy. Capture-based targeted sequencing was performed in a cohort of 86 stage I invasive adenocarcinoma (IAC) patients spanning 5 subtypes using a panel consisting of 168 lung cancer-related genes. Results: Our analysis identified a total of 302 genomic alterations. Five subtypes showed distinct mutation profiles with LPA, APA, PPA, MPC and SPA had an average mutation rate of 1.95 (range: 0–5), 2.56 (range: 1–6), 3.5 (range: 1–7), 3.75 (range: 1-8) and 6.05 (range: 2-12), respectively (p = 4.17e-06). In this cohort, 96.55% (83/86) of all patients had mutations in classic lung cancer drivers with EGFR (73.3%), KRAS (9.3%), ALK (4.7%) and MET (4.7%) being the most commonly mutated drivers. TP53 is the top mutated tumor suppressor gene. It has been reported that SPA and MPC have unfavorable prognosis comparing to the rest subtypes. Interestingly, LRP1B mutations, which has been reported to be associated with high tumor mutation burden and better response to immunotherapy, were only detected from 5 SPA patients (p = 0.001). No MPC patients from this cohort harbored LRP1B mutations. Conclusions: We revealed distinctive mutation landscape of the 5 major histological subtypes of LADC, evident by distinctive average mutation rate with SPA and PLA having the highest and lowest average mutation rate, respectively. Furthermore, we also showed that SPA patients harboring LRP1B mutations may benefit from immunotherapy.

CT-Guided Core Biopsy for Peripheral Sub-solid Pulmonary Nodules to Predict Predominant Histological and Aggressive Subtypes of Lung Adenocarcinoma.

Adenocarcinoma is the most common type of lung cancer, and pre-operative biopsy plays an important role to determine its major subtypes. As proposed by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) in 2011, the predominant histological subtype of adenocarcinoma is an indicator of outcomes and recurrence rate. However, the value of CT-guided core biopsy in predicting the predominant subtype and detecting the presence of an aggressive subtype of adenocarcinoma, peripheral sub-solid nodule, has less been discussed. We retrospectively reviewed 318 consecutive peripheral sub-solid nodules that underwent percutaneous CT-guided lung biopsy and surgical resection, between October 2015 and December 2018 and were diagnosed as adenocarcinoma with histological subtype. The subtyping results from biopsy and surgical pathology were compared to evaluate the concordance rate. The overall concordance rate between biopsy and surgical pathology in determining the predominant histological subtype was 64%. Better concordance was found in small tumors (≤ 2cm), in predicting either predominant histology (χ2 = 7.091, P = 0.008) or high grade adenocarcinoma, micropapillary and/or solid subtype, MIP-SOL (χ2 = 22.301, P < 0.001). The analysis of ground glass opacity (GGO) component (C/T ratio) obtained significantly higher accuracy in the pure GGO group than in the other two groups in predicting predominant histology or high grade adenocarcinoma (χ2 = 17.560, P < 0.001 and χ2 = 61.938, P < 0.001, respectively). CT-guided core biopsies provide additional value in predicting the histological subtype of lung adenocarcinoma after surgical resection, especially in small tumors (≤ 2cm) or an initially pure GGO group.