Alveolar space filling ratio as a favorable prognostic factor in small peripheral squamous cell carcinoma of the lung

A novel histopathological feature of spatial tumor-stroma distribution predicts lung squamous cell carcinoma prognosis

We used a mathematical approach to investigate the quantitative spatial profile of cancer cells and stroma in lung squamous cell carcinoma tissues and its clinical relevance. The study enrolled 132 patients with 3-5 cm peripheral lung squamous cell carcinoma, resected at the National Cancer Center Hospital East. We utilized machine learning to segment cancer cells and stroma on cytokeratin AE1/3 immunohistochemistry images. Subsequently, a spatial form of Shannon's entropy was employed to precisely quantify the spatial distribution of cancer cells and stroma. This quantification index was defined as the spatial tumor-stroma distribution index (STSDI). The patients were classified as STSDI-low and -high groups for clinicopathological comparison. The STSDI showed no significant association with baseline clinicopathological features, including sex, age, pathological stage, and lymphovascular invasion. However, the STSDI-low group had significantly shorter recurrence-free survival (5-years RFS: 49.5% vs. 76.2%, p < 0.001) and disease-specific survival (5-years DSS: 53.6% vs. 81.5%, p < 0.001) than the STSDI-high group. In contrast, the application of Shannon's entropy without spatial consideration showed no correlation with patient outcomes. Moreover, low STSDI was an independent unfavorable predictor of tumor recurrence and disease-specific death (RFS; HR = 2.668, p < 0.005; DSS; HR = 3.057, p < 0.005), alongside the pathological stage. Further analysis showed a correlation between low STSDI and destructive growth patterns of cancer cells within tumors, potentially explaining the aggressive nature of STSDI-low tumors. In this study, we presented a novel approach for histological analysis of cancer tissues that revealed the prognostic significance of spatial tumor-stroma distribution in lung squamous cell carcinoma.

Frequent EGFR exon 20 insertion in the so-called peripheral-type squamous cell neoplasm of uncertain malignant potential: a variant of bronchiolar adenoma or under-recognised entity?

INTRODUCTION

Herein we describe a series of rare peripheral pulmonary neoplasms temporarily termed "peripheral type squamous cell neoplasm of uncertain malignant potential (PSCN-UMP)" and investigate their relationship to bronchiolar adenoma (BA) and squamous cell carcinoma (SCC).

MATERIALS AND METHODS

The histologic and immunohistochemical features of 10 PSCN-UMPs and six BAs were compared. Whole exome sequencing (WES) and bioinformatics analysis were performed to further compare the genetic features of PSCN-UMPs, BAs, and NSCLCs.

RESULTS

All PSCN-UMPs were peripherally located and histologically characterised by the lepidic, nested, and papillary proliferation of relatively bland squamous cells, accompanied by entrapped hyperplastic reactive pneumocytes. The basal squamous cells coexpressed TTF1 and squamous markers. Both cellular components exhibited bland morphology and a low proliferative activity. The six BAs met the morphologic and immunophenotypic features of proximal-type BA. Genetically, driver mutations, including frequent EGFR exon 20 insertions, were found in PSCN-UMPs, while the KRAS mutation, BRAF mutation, and ERC1::RET fusion were detected in BAs. PSCN-UMPs also shared some alterations with BAs in mutational signatures, while copy number variants (CNV) were enriched in MET and NKX2-1 in PSCN-UMP and MCL1, MECOM, SGK1, and PRKAR1A in BA.

CONCLUSION

PSCN-UMPs exhibited the proliferation of bland squamous cells accompanied by entrapped pneumocytes and frequent EGFR exon 20 insertions, which showed distinct features from BAs and SCCs. Recognition of this specific entity will help to expand the morphologic and molecular spectrum of peripheral lung squamous neoplasms.

Radiological precursor lesions of lung squamous cell carcinoma: Early progression patterns and divergent volume doubling time between hilar and peripheral zones

OBJECTIVES

This study investigated the early progression patterns of lung squamous cell carcinoma (SqCC) on computed tomography (CT) images.

MATERIALS AND METHODS

In total, 65 patients with SqCC who underwent surgical resection and two CT scans separated by an interval of at least 6 months were enrolled. We categorized the findings of the initial and at-diagnosis CT images into five patterns as previously reported. The volume doubling time (VDT) was calculated for measurable lesions.

RESULTS

A single nodule pattern on CT images at-diagnosis was most common in 56 (86.2 %) patients, in line with practical clinical findings. However, the patterns were diverse in the initial images, with 28 (43.1 %) patients displaying atypical findings, including multiple nodules (3.1 %), endobronchial lesions (20.0 %), subsolid nodules (10.8 %), and cyst wall thickening (9.2 %). All endobronchial lesions were located in the central/middle zone of the lung field, whereas lesions presented as multiple nodules, subsolid nodules, and cyst wall thickening were predominantly observed in the peripheral zone. The differences in the developed zones were reflected in the median VDT, and the tumors with an initial endobronchial pattern had a significantly shorter VDT than those with a subsolid nodule pattern (median: 140 days vs 276 days, p < 0.001).

CONCLUSIONS

Lung SqCC initiated with various CT image patterns, although most tumors ultimately developed a single nodule pattern by diagnosis. The initial CT image patterns differed between the hilar and peripheral zones, suggesting a difference in the progression scheme, which was also supported by differences in VDT.

Nonsmall cell lung carcinoma: diagnostic difficulties in small biopsies and cytological specimens

The pathological and molecular classification of lung cancer has become substantially more complex over the past decade. For diagnostic purposes on small samples, additional stains are frequently required to distinguish between squamous cell carcinoma and adenocarcinoma. Subsequently, for advanced nonsquamous cell nonsmall cell lung carcinoma (NSCLC) patients, predictive analyses on epidermal growth factor receptor, anaplastic lymphoma kinase and ROS1 are required. In NSCLCs negative for these biomarkers, programmed death ligand-1 immunohistochemistry is performed. Small samples (biopsy and cytology) require “tissue” management, which is best achieved by the interaction of all physicians involved.

Epithelial mesenchymal transition (EMT) and non-small cell lung cancer (NSCLC): a mutual association with airway disease

NSCLC is a leading cause of morbidity and mortality worldwide. It includes adeno- and squamous cell carcinoma. In the background, COPD and smoking play a vital role in development of NSCLC. Local progression and metastasis of NSCLC has been associated with various mechanisms, but in particular by a process called epithelial mesenchymal transition (EMT), which is implicated in COPD pathogenesis. In this study, we have investigated whether expression of EGFR (activation marker) and S100A4, vimentin and N-cadherin (as EMT) is different both in central and leading edge of NSCLC and to what extent related to EMT activity of both small and large airways, stage and differentiation of NSCLC. We have investigated EMT biomarkers (S100A4, vimentin, and N-cadherin), an epithelial activation marker (EGFR) and a vascularity marker (Type-IV collagen) in surgically resected tissue from patients with NSCLC (adeno- and squamous cell carcinoma), and compared them with expression in the corresponding non-tumorous airways. EGFR, S100A4, vimentin, N-cadherin expression was higher in tumor cells located at the peripheral leading edge of NSCLC when compared with centrally located tumor cells of same subjects (P < 0.01). Type-IV collagen-expressing blood vessels were also more at the leading edge in comparison with central parts of NSCLC. EGFR and S100A4 expression was related to differentiation status (P < 0.05) and TNM stage (P < 0.05) of NSCLC. Moreover, EMT markers in the leading edge were significantly related to airway EMT activity, while peripheral edge vascularity of squamous cell carcinoma only was significantly related to large airway Rbm vascularity (P < 0.05). EGFR- and EMT-related protein expression was markedly high in the peripheral leading edge of NSCLCs and related to tumor characteristics associated with poor prognosis. The relationships between EMT-related tumor biomarker expression and those in the airway epithelium and Rbm provide a background for utility of airway changes in clinical settings.

Spread through Air Spaces (STAS) Is an Independent Predictor of Recurrence and Lung Cancer-Specific Death in Squamous Cell Carcinoma

INTRODUCTION

Spread through air spaces (STAS) is a recently recognized pattern of invasion in lung adenocarcinoma; however, it has not yet been characterized in squamous cell carcinoma (SCC).

METHODS

We reviewed 445 resected stage I to III lung SCCs and investigated the clinical significance of STAS. Cumulative incidence of recurrence and lung cancer-specific death were evaluated by competing risks analyses and overall survival by Cox models.

RESULTS

Of the total 445 patients, 336 (76%) were older than 65 years. Among the 273 patients who died, 91 (33%) died of lung cancer whereas the remaining ones died of competing events or unknown cause. STAS was observed in 132 patients (30%) and the frequency increased with stage. The cumulative incidences of any, distant, and locoregional recurrence as well as lung cancer-specific death were significantly higher in patients with STAS compared with in those without STAS, whereas there was no statistically significant difference in overall survival. In multivariable models for any recurrence and lung cancer-specific death, STAS was an independent predictor for both outcomes (p = 0.034 and 0.016, respectively).

CONCLUSION

STAS was present in one-third of resected lung SCCs. In competing risks analysis in a cohort in which three-fourths of the patients were elderly, STAS was associated with lung cancer-specific outcomes. Our findings suggest that STAS is one of the most prognostically significant histologic findings in lung SCC.

Interstitial growth as an aggressive growth pattern in primary lung cancer

PURPOSE

Interstitial growth (IG), which is defined as tumor cells continuously growing into the alveolar septa at the tumor periphery, was originally reported as a growth pattern of metastatic sarcoma of the lung. On the other hand, IG in the primary lung cancers has not been well described. This study aimed to examine clinicopathological features of primary lung cancer that harbors IG.

METHODS

A total of 2558 primary lung cancers which were resected from 2003 to 2012 in our hospital were examined for IG. We compared clinicopathological data and prognoses between patients with IG(+) and IG(-) specimens.

RESULTS

Thirty-three cases out of 2558 (1.3 %) had IG components. IG was significantly more associated with positive smoking history, advanced pathological stage, presence of vascular invasion and pleural invasion. Thirty-three IG(+) cases include nine pleomorphic carcinoma, nine squamous cell carcinoma and eight adenocarcinoma. Interestingly, nine (24 %) out of 38 pleomorphic carcinoma specimens had IG components, which was a higher rate than any other histological subtypes. The IG(+) cancers had significantly shorter overall and recurrence-free survival than did the IG(-) cancers.

CONCLUSIONS

We firstly reported on IG in various types of primary lung cancer. IG appears to be a sign of an aggressive lung cancer phenotype, mainly found in pleomorphic carcinoma.

The prognostic value of morphologic findings for lung squamous cell carcinoma patients

BACKGROUND

Novel histopathological prognostic features for squamous cell carcinoma (SCC) of lung, such as tumor budding, mitotic rate, tumor stroma ratio, stroma type, stromal inflammation and necrosis, have been evaluated in the literature. In this study, the prognostic value of multiple morphological features is assessed in lung SCC.

MATERIALS AND METHODS

This study reports on seventy-six patients with lung SCC treated with complete surgical excision. Tumor size, tumor stage, lymph node status, lymphovascular invasion, histopathologic grade, mitotic count, necrosis, tumor budding, tumor stroma ratio, stroma type, stromal lymphoplasmacytic reaction and ratios of stromal plasma cells and their relationship with the prognosis were evaluated. Univariate and multivariate analyses were performed for histopathological markers for local disease free survival (LDFS), distant disease free survival (DDFS), overall disease free survival (ODFS) and overall survival (OS).

RESULTS

The univariate prognostic analysis of the pathological factors revealed that the pathological stage (OS: p=0.001, DDFS: p=0.040), lymph node metastases (OS: p=0.013), mitotic index (OS: p=0.026), tumor necrosis (DDFS: p=0.013, ODFS: p=0.021) and tumor size (OS: p=0.002) had a prognostic significance. The multivariate analysis demonstrated that the pathological stage (OS: p=0.021), tumor size (OS: p=0.044), lymph node status (DDFS: p=0.019, ODFS; p=0.041) and necrosis (ODFS: p=0.048) were independent prognostic factors.

CONCLUSIONS

Although many histopathological factors have recently been proposed as important prognostic markers, we only found significant results for mitotic index and tumor necrosis, as well as the well known parameters such as tumor stage and lymph node status. To the best of our knowledge, this is the first study evaluating such a wide range of morphological prognostic factors in lung SCC.

Comparison of the expression levels of molecular markers among the peripheral area and central area of primary tumor and metastatic lymph node tumor in patients with squamous cell carcinoma of the lung

PURPOSE

Immunohistochemical analysis for the identification of clinically relevant biomarkers is important. However, there have been no detailed reports about the heterogeneous expressions of the various markers in squamous cell carcinoma of the lung.

METHODS

A total of 113 patients with squamous cell carcinoma of the lung with lymph node metastasis were included. The expression levels of 9 molecules (E-cadherin, S100A4, CD44, ALDH1, SOX2, EGFR, HER2, FGFR1 and VEGFR2) in the peripheral area and central area of primary tumor and metastatic lymph nodes were evaluated by immunohistochemistry. The differences in the staining scores of these molecules among the three areas were assessed. We also analyzed the relationships between the expression levels of these molecules and the recurrence-free survival.

RESULTS

The E-cadherin expression was higher in the central area than in the peripheral area and metastatic lymph nodes (median staining score: 60 vs. 50, 30); the CD44 expression was higher in the central area than in the metastatic lymph nodes (117 vs. 90); and the EGFR expression was higher in the central area than in the peripheral area and metastatic lymph nodes (163 vs. 130, 110). Low CD44 expression in the central area, low EGFR expression in the peripheral area and high SOX2 expression in the metastatic lymph nodes were associated with a shorter recurrence-free survival (p < 0.01, p = 0.02, p = 0.03, respectively).

CONCLUSIONS

Our findings confirmed that some molecular markers exhibited different expression levels in anatomically different areas and suggested that area-by-area immunohistochemical analysis for biomarkers may provide useful information for more precise prediction of the recurrence.

Novel medium-term carcinogenesis model for lung squamous cell carcinoma induced by N-nitroso-tris-chloroethylurea in mice

Targeted treatments for lung cancer based on pathological diagnoses are required to enhance therapeutic efficacy. There are few well-established animal models for lung squamous cell carcinoma although several highly reproducible mouse models for lung adenoma and adenocarcinoma are available. This study was carried out to establish a new lung squamous cell carcinoma mouse model. In the first experiment, female A/J mice were painted topically on back skin twice weekly with 75 μL 0.013 M N-nitroso-tris-chloroethylurea for 2, 4, and 8 weeks (n = 15-20 per group) as initiation of lung lesions, and surviving mice were killed at 18 weeks. In the second experiment, mice were treated as above for 4 weeks and killed at 6, 12, or 18 weeks (n = 3 per group). Lung lobes were subjected to histopathological, immunohistochemical, immunoblotting, and ultrastructural analyses. In the case of treatment for 2, 4, and 8 weeks, incidences of lung squamous cell carcinoma were 25, 54, and 71%, respectively. Cytokeratin 5/6 and epidermal growth factor receptor were clearly expressed in dysplasia and squamous cell carcinoma. Desmosomes and tonofilaments developed in the squamous cell carcinoma. Considering the carcinogenesis model, we conclude that 2 or 4 weeks of N-nitroso-tris-chloroethylurea treatment may be suitable for investigating new chemicals for promotional or suppressive effects on lung squamous cell carcinoma.

Classification of lung cancer: proposals for change?

Clinical need and developments in pathology and molecular biology require our cancer classifications to be constantly updated to keep them relevant and useful. A review of lung cancer classification is due and has been initiated with new proposals on classification of lung adenocarcinoma. Other major lung cancer types also deserve a similar consideration. As well as addressing the categories of tumor, as signed out in surgical resection specimens, recent proposals on small diagnostic-sample reporting would be an important addition to any new classification. The huge increase in data on the molecular biology of lung cancer has improved our understanding of these diseases, has driven improved therapy for some patients, and must be reflected in the way lung cancer is classified.

Morphologic and clinicopathologic features of lung squamous cell carcinomas expressing Sox2

Sox2 amplification was recently reported as a common event in squamous cell carcinomas (SCCs) occurring at different anatomic sites including the lung. The objective of the study was to determine morphologic and clinicopathologic characteristics of lung SCCs with respect to Sox2 protein expression and gene amplification. One hundred forty-seven surgically treated non-small cell lung carcinomas were analyzed for Sox2 gene amplification by using fluorescence in situ hybridization and protein expression using immunohistochemical analysis. SCC showed more frequent Sox2 protein expression (52/66; 79%) than adenocarcinomas (ADC) (14/76; 18%) (P < .0001). Similarly, Sox2 amplification was more frequent in SCCs (52/70; 72%) than in ADCs (6/77; 8%) (P < .0001). Sox2 protein expression was associated with better overall survival in SCC (66 vs 14 months; P =.048). SCC with basaloid differentiation and severe nuclear atypia exhibited more intense Sox2 protein expression than other tumors. Sox2 appears to be an important gene in lung squamous cell carcinogenesis that in particular drives the development of poorly differentiated tumors.

The changing pathology of lung cancer

Lung cancer classification is of paramount importance in determining the treatment for oncologic patients. Most lung cancers are non-small cell lung carcinomas (NSCLC), which are further subclassified into squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. Lung neuroendocrine tumors are subclassified into typical carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma. In NSCLC in particular, the histologic classification and tumor mutation analysis are central to today's targeted therapy and personalized treatment. This article discusses the current diagnostic criteria for classification of NSCLC and lung neuroendocrine tumors and implications for oncologic treatment.