Association of c-Met phosphorylation with micropapillary pattern and small cluster invasion in pT1-size lung adenocarcinoma

Imaging phenotyping using 18F-FDG PET/CT radiomics to predict micropapillary and solid pattern in lung adenocarcinoma

OBJECTIVES

To develop and validate a machine learning model using 18F-FDG PET/CT radiomics signature and clinical features to predict the presence of micropapillary and solid (MP/S) components in lung adenocarcinoma.

METHODS

Eight hundred and forty-six patients who underwent preoperative PET/CT with pathologically confirmed adenocarcinoma were enrolled. After segmentation, 1688 radiomics features were extracted from PET/CT and selected to construct predictive models. Then, we developed a nomogram based on PET/CT radiomics integrated with clinical features. Receiver operating curves, calibration curves, and decision curve analysis (DCA) were performed for diagnostics assessment and test of the developed models for distinguishing patients with MP/S components from the patients without.

RESULTS

PET/CT radiomics-clinical combined model could well distinguish patients with MP/S components from those without MP/S components (AUC = 0.87), which performed better than PET (AUC = 0.829, p < 0.05) or CT (AUC = 0.827, p < 0.05) radiomics models in the training cohort. In test cohorts, radiomics-clinical combined model outperformed the PET radiomics model in test cohort 1 (AUC = 0.859 vs 0.799, p < 0.05) and the CT radiomics model in test cohort 2 (AUC = 0.880 vs 0.829, p < 0.05). Calibration curve indicated good coherence between all model prediction and the actual observation in training and test cohorts. DCA revealed PET/CT radiomics-clinical model exerted the highest clinical benefit.

CONCLUSION

18F-FDG PET/CT radiomics signatures could achieve promising prediction efficiency to identify the presence of MP/S components in adenocarcinoma patients to help the clinician decide on personalized treatment and surveillance strategies. The PET/CT radiomics-clinical combined model performed best. CRITICAL RELEVANCE STATEMENT: 18F-FDG PET/CT radiomics signatures could achieve promising prediction efficiency to identify the presence of micropapillary and solid components in adenocarcinoma patients to help the clinician decide on personalized treatment and surveillance strategies.

Establishment and visualization of a model based on high-resolution CT qualitative and quantitative features for prediction of micropapillary or solid components in invasive lung adenocarcinoma

OBJECTIVE

To predict the existence of micropapillary or solid components in invasive adenocarcinoma, a model was constructed using qualitative and quantitative features in high-resolution computed tomography (HRCT).

METHODS

Through pathological examinations, 176 lesions were divided into two groups depending on the presence or absence of micropapillary and/or solid components (MP/S): MP/S- group (n = 128) and MP/S + group (n = 48). Multivariate logistic regression analyses were used to identify independent predictors of the MP/S. Artificial intelligence (AI)-assisted diagnostic software was used to automatically identify the lesions and extract corresponding quantitative parameters on CT images. The qualitative, quantitative, and combined models were constructed according to the results of multivariate logistic regression analysis. The receiver operating characteristic (ROC) analysis was conducted to evaluate the discrimination capacity of the models with the area under the curve (AUC), sensitivity, and specificity calculated. The calibration and clinical utility of the three models were determined using the calibration curve and decision curve analysis (DCA), respectively. The combined model was visualized in a nomogram.

RESULTS

The multivariate logistic regression analysis using both qualitative and quantitative features indicated that tumor shape (P =  0.029 OR =  4.89; 95% CI 1.175-20.379), pleural indentation (P = 0.039 OR =  1.91; 95% CI 0.791-4.631), and consolidation tumor ratios (CTR) (P < 0.001; OR = 1.05; 95% CI 1.036-1.070) were independent predictors for MP/S + . The areas under the curve (AUC) of the qualitative, quantitative, and combined models in predicting MP/S + were 0.844 (95% CI 0.778-0.909), 0.863 (95% CI 0.803-0.923), and 0.880 (95% CI 0.824-0.937). The combined model of AUC was the most superior and statistically better than qualitative model.

CONCLUSION

The combined model could assist doctors to evaluate patient's prognoses and devise personalized diagnostic and treatment protocols for patients.

Prognostic impact of lung adenocarcinoma second predominant pattern from a large European database

BACKGROUND AND OBJECTIVES

Adenocarcinoma patterns could be grouped based on clinical behaviors: low- (lepidic), intermediate- (papillary or acinar), and high-grade (micropapillary and solid). We analyzed the impact of the second predominant pattern (SPP) on disease-free survival (DFS).

METHODS

We retrospectively collected data of surgically resected stage I and II adenocarcinoma.

SELECTION CRITERIA

anatomical resection with lymphadenectomy and pathological N0. Pure adenocarcinomas and mucinous subtypes were excluded. Recurrence rate and factors affecting DFS were analyzed according to the SPP focusing on intermediate-grade predominant pattern adenocarcinomas.

RESULTS

Among 270 patients, 55% were male. The mean age was 68.3 years. SPP pattern appeared as follows: lepidic 43.0%, papillary 23.0%, solid 14.4%, acinar 11.9%, and micropapillary 7.8%. The recurrence rate was 21.5% and 5-year DFS was 71.1%. No difference in DFS was found according to SPP (p = .522). In patients with high-grade SPP, the percentage of SPP, age, and tumor size significantly influenced DFS (p = .016). In patients with lepidic SPP, size, male gender, and lymph-node sampling (p = .005; p = .014; p = .038, respectively) significantly influenced DFS.

CONCLUSIONS

The impact of SPP on DFS is not homogeneous in a subset of patients with the intermediate-grade predominant patterns. The influence of high-grade SPP on DFS is related to its proportion in the tumor.

Micropapillary Predominant Lung Adenocarcinoma in Stage IA Benefits from Adjuvant Chemotherapy

PURPOSE

The benefit of adjuvant chemotherapy remains unknown for patients with stage IA micropapillary predominant (MPP) lung adenocarcinoma (ADC). This study investigated the effect of adjuvant chemotherapy in ADC and MPP patients in stage IA.

METHODS

A total of 5220 stage IA lung ADC patients from SEER database and 152 MPP subtype patients from Qilu Hospital of Shandong University were retrospectively analyzed. Propensity score matching analysis was used to adjust the confounding factors. The benefits of improved overall survival (OS) or progression-free survival (PFS) from adjuvant chemotherapy in patients with resected stage IA ADC or MPP patients were investigated.

RESULTS

Based on SEER database, for ADC patients in stage IA, chemotherapy (no vs. yes: hazard ratio [HR]: 0.674, 95% confidence interval [CI] 0.474-0.958, P = 0.030), together with radiotherapy (no vs. yes: HR: 0.519, 95% CI 0.358-0.751, P = 0.001), race, gender, age, and T stage were all statistically significant independent factors for OS. However, in propensity model, there was no significant difference in OS between patients who received adjuvant chemotherapy and those who did not. Only age was a significant prognostic predictor for OS. For patients with MPP subtype in stage IA, multivariate analysis revealed that chemotherapy (no vs. yes: HR: 2.054, 95% CI 1.085-3.886, P = 0.027) as well as T stage were prognostic predictors for OS. Chemotherapy (no vs. yes: HR: 2.205, 95% CI 1.118-4.349, P = 0.022) and T stage also were significant predictors for PFS.

CONCLUSIONS

Adjuvant chemotherapy is a favorable prognostic factor for MPP patients in stage IA but not for lung ADC patients. MPP subtype could benefit from adjuvant chemotherapy.

Clinicopathological and genetic characteristics associated with brain metastases from lung adenocarcinoma and utility as prognostic factors

Brain metastases (BM) are common in patients with lung adenocarcinoma, and represent a significant cause of morbidity in the disease. A more comprehensive understanding of the clinicopathological characteristics that serve as prognostic factors for survival in patients with BM from lung adenocarcinoma may aid in informing treatment strategies for this patient population. In the present study, clinicopathological factors, including EGFR mutation status, were evaluated in 59 patients who were diagnosed with BM from lung adenocarcinoma, and underwent BM resection between January 1985 and December 2014 at Fukuoka University Hospital. The most frequent subtype of BM from lung adenocarcinoma was solid adenocarcinoma (57.6%), followed by papillary adenocarcinoma (22.0%) and acinar adenocarcinoma (18.6%). A total of 14 patients (23.7%) exhibited EGFR mutations, which were significantly associated with female sex (9/14, 64.3%), non-smoker status (8/14, 57.1%), BM in the frontal lobes (9/14, 64.3%) and papillary adenocarcinoma (5/14, 35.7%). Statistical analysis revealed a significant association between non-smoker status and BM in the frontal lobes, and more favorable disease prognosis. The results of the present study suggest that histological and genetic analysis of tissue from BM provides information useful for managing treatment of patients with resectable BM arising from lung adenocarcinoma.

The more the micropapillary pattern in stage I lung adenocarcinoma, the worse the prognosis-a retrospective study on digitalized slides

Although the majority of lung adenocarcinomas show mixed pattern, only the predominant component is taken into account according to the novel classification. We evaluated the proportion of different patterns and their impact on overall survival (OS) and disease-free survival (DFS). Patterns were recorded according to predominance and their proportions were rated and calculated by objective area measuring on digitalized, annotated slides of resected stage I lung adenocarcinomas. Spearman's rank correlation, Kaplan-Meier models and the log rank test were used for statistical evaluation. Two hundred forty-three stage I adenocarcinoma were included. Lepidic pattern is more frequent in tumours without recurrence (20 vs. 8%), and lepidic predominant tumours have favourable prognosis (OS 90.5%, DFS 89.4%), but proportions above 25% are not associated with improving outcome. Solid and micropapillary patterns are more frequent in patients with recurrence (48 vs. 5% and 13 vs. 4%) and predominance of each one is associated with unfavourable prognosis (OS 64.1%, DFS 56.3% and OS 28.1%, DFS 28.1%, respectively). Above 25%, a growing proportion of solid or micropapillary pattern is not associated with worsening prognosis. In contrast, tumours having micropapillary pattern as secondly predominant form a different intermediate group (OS 51.1%, DFS 57.8%). Our study was based on measured area of each growth pattern on all available slides digitalized. This is the most precise way of determining the size of each component from the material available. We propose using predominant and secondly predominant patterns for prognostic purposes, particularly in tumours having solid or micropapillary patterns.

Protein overexpression and gene amplification of cellular mesenchymal-epithelial transition factor is associated with poor prognosis in micropapillary-predominant subtype pulmonary adenocarcinoma

Micropapillary-predominant subtype pulmonary adenocarcinoma (MPPAC) is a subtype of lung cancer with poor prognosis. Cellular mesenchymal-epithelial transition factor (c-MET) is a promising pharmaceutic target found to be associated with the survival of patients with pulmonary adenocarcinoma. In this study, we aimed to analyze c-MET protein overexpression and gene amplification in MPPAC samples and to elucidate their relationship with the clinicopathological characteristics of the patients. c-MET protein expression was examined by immunohistochemical analyses, and gene amplification was detected by fluorescence in situ hybridization. A total of 86 MPPAC cases were included in this study. The prevalence of c-MET protein overexpression and gene amplification were 62.8% and 10.5%, respectively. C-MET protein overexpression was significantly associated with smoking status, lymphatic and venous invasion, and tumor-node-metastasis stage (P = .014, P = .040, and P = .004, respectively), but c-MET gene amplification showed no relation with any of these characteristics. Univariate analysis revealed that pleural invasion, lymph node metastasis, lymphatic and venous invasion, tumor-node-metastasis stage, c-MET protein overexpression, and c-MET gene amplification were associated with poor prognosis (P = .041, P < .001, P = .001, P < .001, P = .001 and P = .001, respectively), but only c-MET gene amplification was an independent prognostic marker (P = .04). These results indicated that c-MET is an important biomarker. Also, c-MET protein overexpression and gene amplification are highly related to poor prognosis in patients with MPPAC.

Tumor Spread Through Air Spaces Is an Independent Predictor of Recurrence-free Survival in Patients With Resected Lung Squamous Cell Carcinoma

Tumor spread through air spaces (STAS) is a newly recognized pattern of invasion in lung adenocarcinoma. However, clinical significance of STAS has not yet been characterized in lung squamous cell carcinoma. In this study, we investigated whether STAS could determine clinical outcome in Japanese patients with lung squamous cell carcinoma. We reviewed tumor slides from surgically resected lung squamous cell carcinomas (n=216). STAS was defined as tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. Tumors were evaluated for histologic subtypes, tumor budding, and nuclear diameter. Recurrence-free survival (RFS) was analyzed using the log-rank test and the Cox proportional hazards model. Tumor STAS was observed in 87 patients (40%), increasing incidence with lymph node metastasis (P=0.037), higher pathologic stage (P=0.026), and lymphatic invasion (P=0.033). All cases with STAS showed a solid nest pattern. The 5-year RFS for patients with STAS was significantly lower than it was for patients without STAS in all patients (P=0.001) and in stage I patients (n=134; P=0.041). On multivariate analysis, STAS was an independent prognostic factor of a worse RFS (hazard ratio=1.61; P=0.023). Patients with STAS had a significantly increased risk of developing locoregional and distant recurrences (P=0.012 and 0.001, respectively). We found that tumor STAS was an independent predictor of RFS in patients with resected lung squamous cell carcinoma, and it was associated with aggressive tumor behavior.

A Grading System Combining Tumor Budding and Nuclear Diameter Predicts Prognosis in Resected Lung Squamous Cell Carcinoma

For lung squamous cell carcinomas, there are no histologic findings that have been universally accepted as prognostic factors. Tumor budding and nuclear grade have been recognized as prognostic factors in other carcinomas. In this study, we investigated whether pathologic findings could determine clinical outcome in Japanese patients with lung squamous cell carcinomas. Tumor slides from surgically resected lung squamous cell carcinomas (1999 to 2012) were reviewed (n=216). Tumors were evaluated for histologic subtypes, differentiation, tumor budding, nuclear diameter, and mitosis. Recurrence-free survival (RFS) and overall survival (OS) were analyzed using the log-rank test and the Cox proportional hazards model. Tumor budding and large nuclei were independent prognostic factors of a worse RFS (P<0.001 and P=0.002, respectively) and a worse OS (P<0.001 and P=0.038, respectively) on multivariate analysis after adjustment for pathologic stage and lymphatic invasion. However, histologic subtypes, differentiation, and mitotic count did not correlate with prognosis. A grading system combining tumor budding and nuclear diameter was an independent prognostic factors of a worse RFS (grade 2 vs. 1, hazard ratio [HR]=2.91; P<0.001, and grade 3 vs. 1, HR=7.60, P<0.001) and a worse OS (grade 2 vs. 1, HR=2.15; P=0.014, and grade 3 vs. 1, HR=4.54, P<0.001). We found that a grading system combining tumor budding and nuclear diameter was a significant prognostic factor among Japanese patients with resected lung squamous cell carcinoma.

Preferential Localization of MET Expression at the Invasion Front and in Spreading Cells Through Air Spaces in Non-Small Cell Lung Carcinomas

The involvement of the HGF/MET pathway in acquisition of an invasive phenotype in non-small cell lung carcinomas (NSCLCs) suggests that MET inhibitors might prove effective against these cancers, but clinical trials have yielded conflicting results. The aim of our study was to evaluate how intratumoral heterogeneity (ITH) of MET staining affects the determination of MET status for therapeutic purposes. We analyzed 64 NSCLC samples, including 33 adenocarcinomas (ADCs) and 31 squamous cell carcinomas (SCCs). We used immunohistochemistry to detect MET and phospho-MET on whole slides and determined the MET SP44 immunoscore and the H-score. A high METMab score (2+/3+) was observed in 34% of NSCLCs and was more prevalent in ADCs (52%) than in SCCs (16%). We found ITH in 73% of ADCs and 77% of SCCs, with higher levels of MET and phospho-MET at the invasion front (in 52% of ADCs and 22% of SCCs) and in tumor cells spreading through air spaces in ADCs. Within-sample ITH was high in 40% of the ADCs and 29% of the SCCs. When different samples from the same tumor were compared, discordant assessments (high MET vs. low MET) were made for 12% of the ADCs and 10% of the SCCs. C-MET and phospho-MET overexpression occurred preferentially in ADCs and in areas involved in tumor progression, in support of the view that MET activation plays a role in the development of an invasive phenotype in NSCLC. To use MET status adequately as a biomarker, one must take the resulting high level of ITH into account.

Factors predicting occult lymph node metastasis in completely resected lung adenocarcinoma of 3 cm or smaller

OBJECTIVES

The aim of the study is to demonstrate the relationship between clinicopathological variables and occult lymph node metastasis in resected lung adenocarcinoma.

METHODS

The clinicopathological characteristics of 471 patients with clinical N2-negative status undergoing resection for lung adenocarcinoma of 3 cm or smaller at Taipei Veterans General Hospital between 2004 and 2012 were retrospectively reviewed. The association between clinicopathological variables and lymph node metastasis was analysed by univariate and multivariate logistic regression.

RESULTS

Among the 471 patients, there were 386 (82.0%) patients with pathological N0 status, 35 (7.4%) with pathological N1 status and 50 (10.6%) with pathological N2 status. Greater tumour size (P = 0.002), presence of a micropapillary pattern (P < 0.001), presence of a solid pattern (P < 0.001) and predominant pattern group (micropapillary/solid predominant) (P = 0.001) were significantly associated with higher percentage of occult N2 lymph node metastasis. In multivariate analysis, greater tumour size (P = 0.008), presence of micropapillary pattern (P < 0.001) and presence of solid pattern (P = 0.001) were significant predictors of occult N2 lymph node metastasis in tumours of 3 cm or smaller. When histological pattern was entered as the predominant pattern in multivariate analysis, micropapillary/solid predominant pattern (P = 0.005) was also a significant predictor of occult N2 lymph node metastasis.

CONCLUSIONS

The presence of micropapillary or solid pattern, as well as micropapillary/solid predominant pattern, is significantly associated with occult N2 lymph node metastasis in lung adenocarcinoma. Radical mediastinal lymph node dissection may help to identify occult lymph node metastasis in these patients.

Clinical impacts of a micropapillary pattern in lung adenocarcinoma: a review

Lung adenocarcinoma with a micropapillary pattern (MPPAC) has recently drawn increased attention among researchers. Micropapillary-predominant adenocarcinoma (MPA), which is defined by micropapillary pattern (MPP), is the primary histological pattern observed semiquantitatively in 5% increments on resection specimens, and MPA was formally determined to be a new histological subtype according to the new multidisciplinary classification in 2011. According to published studies, MPPAC is most common in males and nonsmokers and is associated with lymphatic invasion, pleural invasion, and lymph node metastases. MPPAC often presents as part-solid and lobulated nodules in computed tomography scans. MPP tends to have a higher maximum standardized uptake value as determined by fluorodeoxyglucose positron emission tomography combined with computed tomography, indicating a high risk of recurrence. Molecular markers, including vimentin, napsin A, phosphorylated c-Met, cytoplasmic maspin, Notch-1, MUC1, and tumoral CD10, may have higher expression in MPPAC than other subtypes; conversely, markers such as MUC4 and surfactant apoprotein A have lower expression in MPPAC. MPPAC with EGFR mutations can benefit from treatment with EGFR tyrosine kinase inhibitors. Furthermore, a complete lobectomy may be more suitable than limited resection for MPPAC because of the low sensitivity of intraoperative frozen sections and the high risk of lymph node metastasis. MPA benefits more from adjuvant chemotherapy than do other histological subtypes, whereas MPA does not benefit from adjuvant radiotherapy. Of note, MPP is associated with poor prognosis in early-stage lung adenocarcinoma, but the prognostic value of MPP is controversial in advanced-stage lung adenocarcinoma.

Tumor islands and spread through air spaces: Distinct patterns of invasion in lung adenocarcinoma

Lung adenocarcinoma is a highly heterogeneous disease and the heterogeneity is associated with various patient outcomes even in early-stage tumors. In order to improve prognostic and predictive values, the IASLC/ATS/ERS international multidisciplinary lung adenocarcinoma classification was put forth in 2011 and it has been adopted in the recently published World Health Organization (WHO) classification of Tumours of the Lung, Pleura, Thymus and Heart 4th edition 2015, and lung adenocarcinomas are classified based on the predominant pattern. The performance of the classification in stratifying patient outcomes after resection of Stage I tumors and predicting molecular alterations has been confirmed by several studies. It also includes the category of minimally invasive adenocarcinoma (MIA) that predicts 100% 5-year recurrence free survival after curative resection similar to adenocarcinoma in situ. The diagnosis of MIA is based on not only size of the invasive component but also the absence of aggressive morphologic features such as pleural and/or lymphovascular invasion. Importantly, the WHO 2015 classification has introduced the concept of air space invasion and includes it as the exclusion criteria for MIA. The air space invasion consists of tumor islands and spread through air spaces (STAS). In this review, we will discuss the two entities and their clinical implications.

Tumor Budding Correlates With the Protumor Immune Microenvironment and Is an Independent Prognostic Factor for Recurrence of Stage I Lung Adenocarcinoma

BACKGROUND

Immune cell infiltration associated with tumor capsule disruption and tumor budding has been shown to reflect invasiveness, metastasis, and unfavorable prognosis in colorectal cancer. We investigated the influence of tumor budding on prognosis and its association with the immune microenvironment in lung adenocarcinoma.

METHODS

Tumor slides from resected stage I lung adenocarcinomas were reviewed (n = 524 and n = 514, for training and validation cohorts, respectively) for assessment of tumor budding. CD3+ and forkhead box P3+ (FoxP3+) lymphocytes, CD68+ macrophages, IL-7 receptor, and IL-12 receptor β2 were analyzed using tissue microarrays constructed from tumor and stroma. Probability of recurrence was calculated using the competing risks method.

RESULTS

In the training cohort, risk of recurrence for high-grade tumor budding was higher than it was for low-grade tumor budding (32% vs 12%, P < .001), which was confirmed in the validation cohort (P = .005). Tumor budding stratified the risk of recurrence for acinar-predominant (22% vs 9%, P < .001), papillary-predominant (22% vs 13%, P = .045), and solid-predominant (39% vs 19%, P = .022) tumors. Tumor budding was associated with higher stromal FoxP3+ lymphocyte infiltration, higher stromal FoxP3/CD3 risk index, higher tumoral and stromal CD68+ macrophage infiltration, and IL-7 receptor overexpression (P < .001, all associations). Tumor budding remained independently associated with recurrence on multivariate analysis (hazard ratio, 1.61; P = .008).

CONCLUSIONS

Tumor budding is an independent prognostic factor of stage I lung adenocarcinoma and correlates with the protumor immune microenvironment. Our findings advocate investigating tumor-immune cell interactions at the invading edge as a biologic driver of tumor aggressiveness.

[Advances of Pulmonary Adenocarcinoma with Micropapillary Pattern]

伴微乳头结构(micropapillary pattern, MPP)肺腺癌是一种临床少见的具有高度侵袭性的恶性肿瘤，近年来因其高死亡率被人们所重视。2011年关于肺腺癌的病理新分类将其作为一种独立的病理类型，此后针对该类肺癌个体化治疗的相关研究逐渐展开。近期的相关研究发现，伴MPP肺腺癌在转移机制、临床病理学、影像学、治疗及预后方面具有显著异质性。本文对伴MPP肺腺癌转移机制及相关临床研究进展进行探讨。

Tumor budding in colorectal carcinoma assessed by cytokeratin immunostaining and budding areas: possible involvement of c-Met

Tumor budding/sprouting has been shown to be an independent adverse prognostic factor in T1 and T3N0 colorectal carcinomas, however, its assessment could be improved by more accurate identification of budding carcinoma cells and consideration of budding areas. Moreover, tumor budding mechanisms are yet to be defined. In this study, we evaluated the identification of budding tumor cells by either H&E staining alone or H&E with immunohistochemistry and developed a scoring system based on budding grades and areas. We examined whether the budding score correlated with clinicopathologic features and prognosis and the association between tumor budding/sprouting and c-Met protein expression and phosphorylation and MET gene copy numbers because c-Met is known to play an important role in colorectal carcinoma tumorigenesis. Cytokeratin immunohistochemistry could identify tumors with shorter disease-free survival (DFS) from the low-grade budding group assessed with H&E alone. High budding scores based on budding grade and area were more significantly correlated with DFS than scores obtained using the budding grade alone. In tumors with a high budding score, c-Met expression and phosphorylation levels and MET gene copy numbers were significantly increased at the invasive front compared with those in superficial tumor portions. This study showed for the first time that high levels of phospho-c-Met at the invasive front were significantly associated with a high budding score and shorter DFS. In conclusion, a budding score assessed by budding grades and budding-positive areas correlates highly with clinicopathologic aggressive features of colorectal carcinoma.