Comprehensive analyses unveil novel genomic and immunological characteristics of micropapillary pattern in lung adenocarcinoma.

Lung adenocarcinoma (LUAD) usually contains heterogeneous histological subtypes, among which the micropapillary (MIP) subtype was associated with poor prognosis while the lepidic (LEP) subtype possessed the most favorable outcome. However, the genomic features of the MIP subtype responsible for its malignant behaviors are substantially unknown. In this study, eight FFPE samples from LUAD patients were micro-dissected to isolate MIP and LEP components, then sequenced by whole-exome sequencing. More comprehensive analyses involving our samples and public validation cohorts on the two subtypes were performed to better decipher the key biological and evolutionary mechanisms. As expected, the LEP and MIP subtypes exhibited the largest disease-free survival (DFS) differences in our patients. EGFR was found with the highest mutation frequency. Additionally, shared mutations were observed between paired LEP and MIP components from single patients, and recurrent mutations were verified in the Lung-Broad, Lung-OncoSG, and TCGA-LUAD cohorts. Distinct biological processes or pathways were involved in the evolution of the two components. Besides, analyses of copy number variation (CNV) and intratumor heterogeneity (ITH) further discovered the possible immunosurveillance escape, the discrepancy between mutation and CNV level, ITH, and the pervasive DNA damage response and WNT pathway gene alternations in the MIP component. Phylogenetic analysis of five pairs of LEP and MIP components further confirmed the presence of ancestral EGFR mutations. Through comprehensive analyses combining our samples and public cohorts, PTP4A3, NAPRT, and RECQL4 were identified to be co-amplified. Multi-omics data also demonstrated the immunosuppression prevalence in the MIP component. Our results uncovered the evolutionary pattern of the concomitant LEP and MIP components from the same patient that they were derived from the same initiation cells and the pathway-specific mutations acquired after EGFR clonal mutation could shape the subtype-specificity. We also confirmed the immunosuppression prevalence in the MIP subtype by multi-omics data analyses, which may have resulted in its unfavorable prognosis.

A prognostic nomogram based on a new classification of combined micropapillary and solid components for stage IA invasive lung adenocarcinoma.

BACKGROUND: We aimed to develop a prognostic nomogram based on a new classification of combined micropapillary and solid components in pathological stage IA invasive lung adenocarcinoma (LUAD). METHODS: According to the total proportion of solid and micropapillary components (TPSM), the X-tile software was applied to classify patients into the following three groups: TPSM-low (TPSM-L), TPSM-middle (TPSM-M), and TPSM-high (TPSM-H). The postoperative survival was compared among the three groups. The multivariate Cox regression analysis was performed to identify independent prognostic factors for survival. According to these factors, a nomogram model was developed to provide a personalized prognostic evaluation. RESULTS: A total of 595 patients with pathological stage IA invasive LUAD were included in our study. The 5-year disease-free survival and overall survival rates in patients with TPSM-H and TPSM-M were significantly lower than those with TPSM-L. The multivariate Cox regression analysis revealed that the TPSM classification was an independent prognostic factor for survival. According to TPSM classification, we developed a nomogram model which had good calibration and reliable discrimination ability to evaluate survival. CONCLUSIONS: The nomogram based on the combination of micropapillary and solid components has good prognostic value in predicting postoperative recurrence and survival of patients with pathological stage IA invasive LUAD.

Maturation and abundance of tertiary lymphoid structures are associated with the efficacy of neoadjuvant chemoimmunotherapy in resectable non-small cell lung cancer.

Tertiary lymphoid structures (TLS) existence is correlated with favorable prognosis in many types of cancer including non-small cell lung cancer (NSCLC). However, TLS formation and its relationship with treatment response remains unknown in NSCLC who received anti-PD-1 antibody plus chemotherapy as the neoadjuvant treatment (neoadjuvant chemoimmunotherapy). Here, we investigate TLS maturation and abundance in resectable NSCLC receiving neoadjuvant treatments. We retrospectively collected formalin-fixed paraffin embedded (FFPE) tissues from patients with resectable NSCLC (stage II-IIIA) from three cohorts based on treatment: naïve (N=40), neoadjuvant chemoimmunotherapy (N=40), and neoadjuvant chemotherapy (N=41). The TLS in tumor tissues was detected by immunohistochemical staining, and the differences in TLS maturation and abundance among different treatment groups were analyzed, as well as the relationship with pathological response and prognosis of patients. Multiplex immunofluorescence staining was used to explore the features of immune microenvironment. Higher major pathological response (MPR) rate and pathological complete response (pCR) rate were in the neoadjuvant chemoimmunotherapy group than in the neoadjuvant chemotherapy group (MPR: 45.0% vs 17.1%; pCR: 35.0% vs 4.9%). Among the three cohorts, neoadjuvant chemoimmunotherapy-treated NSCLCs displayed highest TLS maturation and abundance. Both the maturation and abundance of TLS were significantly correlated with MPR in both the neoadjuvant chemoimmunotherapy and the chemotherapy group. Patients with high maturation and abundance of TLS exhibited better disease-free survival (DFS) in all the three cohorts. TLS maturation was also an independent predictor for DFS in the neoadjuvant chemoimmunotherapy and treatment naïve group. Multiplex immunohistochemistry analysis using paired biopsy-surgery samples showed increased infiltration of CD8+T cell and decreased infiltration of M1 and M2 macrophages after neoadjuvant chemoimmunotherapy treatment in patients achieving MPR. There were no significant differences in features of immune cell infiltration for those with mature TLS achieving MPR when cross-compared across the three cohorts. These results demonstrate that TLS maturation is associated with MPR and an independent predictor for DFS in resectable neoadjuvant chemoimmunotherapy-treated NSCLC. The induction of TLS maturation may be a potential mechanism of action of neoadjuvant chemoimmunotherapy in resectable NSCLC.

The Prognostic Value of Non-Predominant Micropapillary Pattern in a Large Cohort of Resected Invasive Lung Adenocarcinoma Measuring ≤3 cm.

The aim of this study was to analyze the influence of non-predominant micropapillary pattern in small sized invasive lung adenocarcinoma. A total of 986 lung adenocarcinoma patients with tumor size ≤3 cm were identified and classified according to the IALSC/ATS/ERS classification. Emphasis was placed on the impact of non-predominant micropapillary pattern on disease-free survival (DFS) and overall survival (OS). The relationship between lung adenocarcinoma subtype and lymph node involvement, EGFR mutation and KRAS mutation was also evaluated. A nomogram was developed to predict the probability of 3- and 5-year OS for these patients. The concordance index and calibration plot were used to validate this model. Among all 986 patients, the percentages of lymph node involvement were: 58.1, 50.0, 33.5, 21.4, 21.1, 10.9, 0, and 0% for micropapillary predominant, solid predominant, acinar predominant, papillary predominant, invasive mucinous adenocarcinoma (IMA), lepidic predominant, minimally invasive adenocarcinoma (MIA), adenocarcinoma in situ (AIS), respectively. The frequency of EGFR mutation in the cases of lepidic predominant, acinar predominant, MIA, micropapillary predominant, papillary predominant, solid predominant, IMA, and AIS were 51.1, 45.2, 44.4, 36.8, 29.3, 26.8, 8.3, and 0%, respectively. A non-predominant micropapillary pattern was observed in 344 (38.4%) invasive adenocarcinoma (IAC), and its presence predicted a poorer DFS (median: 56.0 months vs. 66.0 months, P <0.001) and OS (median: 61.0 months vs. 70.0 months, P <0.001). After propensity score matching, non-predominant micropapillary pattern retained its unfavorable effect on DFS (P = 0.007) and OS (P = 0.001). Multivariate analysis showed that non-predominant micropapillary pattern was identified as an independent prognostic factor for DFS (P = 0.003) and OS (P <0.001) in IAC. The nomogram showed good calibration and reliable discrimination ability (C-index = 0.775) to evaluated the 3- and 5-year OS. This retrospective analysis of patients with small sized IAC suggests the value of non-predominant micropapillary pattern to predict poor prognosis. A reliable nomogram model was constructed to provide personalized survival predictions.