Immunohistochemical expression of TTF-1 in various cytological subtypes of primary lung adenocarcinoma, with special reference to intratumoral heterogeneity

Lung adenocarcinomas with isolated TP53 mutation: A comprehensive clinical, cytopathologic and molecular characterization

BACKGROUND

TP53 mutation is present in about 50.8% of lung adenocarcinomas, frequently in combination with other genetic alterations. However, a rare subset harbors the TP53 mutation alone.

METHODS

Next-generation sequencing was performed in 844 lung adenocarcinomas diagnosed by fine needle aspiration. Fourteen cases (1.7%) showed isolated TP53 alteration and were subjected to a comprehensive analysis.

RESULTS

The average age at diagnosis was 65.7 years (range 48-79); 9 males and 5 females. All were smokers with an average pack-year of 40.7 (range 10-70). Ten had metastases, mostly in the brain (n = 4) and pleura (n = 4). After a follow-up period of up to 102 months, 9 died, 3 were alive free of disease, 1 was alive with disease, and 1 was lost to follow-up. The median survival was 12.2 months. Most tumors exhibited poor differentiation, composed of solid sheets with moderate to severe atypia, increased mitotic activity, and necrotic background. Half were positive for TTF-1 and showed p53 overexpression. PD-L1 was positive in 5 cases. Most alterations were missense mutations in exons 5-8, and this mutation type was associated with p53 overexpression. Tumors with combined missense mutation and truncated protein had higher PD-L1 expression along with a trend towards an increase in tumor mutational burden (TMB). CEBPA deletion of undetermined significance was the most common copy number alteration.

CONCLUSION

Isolated TP53 mutation was seen in association with smoking, high-grade cytomorphologic features, adverse prognosis, and recurrent CEBPA deletions. These tumors tend to have strong PD-L1 expression and high TMB, suggesting potential benefit from immune checkpoint inhibitors. Hence, the recognition of this molecular group has prognostic and therapeutic implications.

TTF-1/p63-Positive Poorly Differentiated NSCLC: A Histogenetic Hypothesis from the Basal Reserve Cell of the Terminal Respiratory Unit

TTF-1 is expressed in the alveolar epithelium and in the basal cells of distal terminal bronchioles. It is considered the most sensitive and specific marker to define the adenocarcinoma arising from the terminal respiratory unit (TRU). TTF-1, CK7, CK5/6, p63 and p40 are useful for typifying the majority of non-small-cell lung cancers, with TTF and CK7 being typically expressed in adenocarcinomas and the latter three being expressed in squamous cell carcinoma. As tumors with coexpression of both TTF-1 and p63 in the same cells are rare, we describe different cases that coexpress them, suggesting a histogenetic hypothesis of their origin. We report 10 cases of poorly differentiated non-small-cell lung carcinoma (PD-NSCLC). Immunohistochemistry was performed by using TTF-1, p63, p40 (ΔNp63), CK5/6 and CK7. EGFR and BRAF gene mutational analysis was performed by using real-time PCR. All the cases showed coexpression of p63 and TTF-1. Six of them showing CK7+ and CK5/6− immunostaining were diagnosed as “TTF-1+ p63+ adenocarcinoma”. The other cases of PD-NSCLC, despite the positivity for CK5/6, were diagnosed as “adenocarcinoma, solid variant”, in keeping with the presence of TTF-1 expression and p40 negativity. A “wild type” genotype of EGFR was evidenced in all cases. TTF1 stained positively the alveolar epithelium and the basal reserve cells of TRU, with the latter also being positive for p63. The coexpression of p63 and TTF-1 could suggest the origin from the basal reserve cells of TRU and represent the capability to differentiate towards different histogenetic lines. More aggressive clinical and morphological features could characterize these “basal-type tumors” like those in the better known “basal-like” cancer of the breast.

A severe combined immunodeficiency disease mouse model of human adenocarcinoma with lepidic-predominant growth

Severe combined immunodeficiency disease (SCID) mice with human lepidic adenocarcinoma were established by the intrabronchial implantation of fresh surgically resected specimens. Human pulmonary adenocarcinoma tissue from 16 different cases was transplanted into SCID mice, and SCID mouse tumors were established from four of these cases (25%). Among the four tumors, the tumor cells of two SCID mice showed replacement lepidic growth of mouse alveolar structures accompanied by multiple intrapulmonary lesions. Human lung carcinoma cell lines showing lepidic growth are rare and the xenograft models using the SCID mouse model developed in the current study will be useful for analyzing the growth and/or progression patterns and clinical behavior of lepidic adenocarcinoma, the major histological subtype of human carcinoma of the lung.

Validation for histology-driven diagnosis in non-small cell lung cancer using hsa-miR-205 and hsa-miR-21 expression by two different normalization strategies

Targeted therapy of non-small cell lung cancer (NSCLC) demands a more accurate tumor classification that is crucial for patient selection in personalized treatment. MicroRNAs constitute a promising class of biomarkers and a helpful tool for the distinction between lung adenocarcinoma (AC) and squamous cell lung carcinoma (SCC). The aim of this study was to evaluate the impact of two different normalization strategies, using U6 snRNA and hsa-miR-103 as reference genes, on hsa-miR-205 and hsa-miR-21 expression levels, in terms of the classification of subtypes of NSCLC. By means of a quantitative real-time polymerase chain reaction (qRT-PCR) microRNA expression levels were evaluated in a classification set of 98 surgically resected NSCLC fresh-frozen samples, and validated findings in an independent set of 42 NSCLC samples. The microRNA expression levels were exploited to develop a diagnostic test using two data normalization strategies. The performance of microRNA profiling in different normalization methods was compared. We revealed the microRNA-based qRT-PCR tests to be appropriate measures for distinguishing between AC and SCC (the concordance of histologic diagnoses and molecular methods greater than 88%). Performance evaluation of microRNA tests, based on the two normalization strategies, showed that the procedure using hsa-miR-103 as reference target has a slight advantage (sensitivity 83.33 and 100% in classification and validation set, respectively) compared to U6 snRNA. Molecular tests based on microRNA expression allow a reliable classification of subtypes for NSCLC and can constitute a useful diagnostic strategy in patient selection for targeted therapy.

Value of thyroid transcription factor (TTF)-1 for diagnosis and prognosis of patients with locally advanced or metastatic small cell lung cancer

Background

The aim of this study was to analyze the frequency of Thyroid Transcription Factor (TTF)-1 expression in small cell lung cancer (SCLC) and its value for the diagnosis of SCLC, the response to first line treatment as well as the prognostic impact on overall survival (OS).

Methods

We analyzed a total of 294 patients (m, n = 184; f, n = 110) with SCLC (stage IIIA, n = 32; IIIB, n = 87; IV, n = 175) diagnosed in our institution between January 2005 and December 2008. Patient’s characteristics comprising age, gender, histology and first line treatment were included into the analyses. For the follow-up of patients the governmental death registrar was used. The TTF-1 immunostaining was prospectively performed. CT scans of all patients were reviewed and response to treatment was evaluated using the Response Evaluation Criteria In Solid Tumors 1.0 (RECIST) criteria.

Results

A total of 221 of the 294 patients were eligible for analysis. Patients with TTF-1-positive SCLC had a median OS of 374 (95% CI 306–442) days. The OS of patients with TTF1-negative SCLC was 290 (95% CI 191–389) days, which was not significantly shorter (p = 0.254). Also stratification for tumor stage did not reveal significant difference in OS. Analyzing the disease control rate (DCR) in patients with metastatic disease (stage IV), we observed a significantly (p = 0.006) improved response to treatment in the group of patients with TTF-1-expression (DCR 86% vs. 56%). Regarding the overall response rates (ORR) in the entire population, there was no difference observed between both subgroups. (TTF-1-pos. 75.3% vs. TTF-1-neg. 71.4%; p = 0.642).

Conclusions

The diagnostic information of TTF-1 in SCLC seems to be limited. TTF-1 had no prognostic value concerning OS, but may serve as a predictor for response to first line chemotherapy.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5811254651472285

Diagnostic and prognostic significances of MUC5B and TTF-1 expressions in resected non-small cell lung cancer

To investigate the relationships between the expression of MUC5B and clinicopathological parameters, the expression of MUC5B was immunohistochemically studied. MUC5B expression was observed in 129 of 198 (65.2%) adenocarcinomas and in 4 of 49 (8.2%) squamous cell carcinomas (P < 0.00001). MUC5B expression was significantly associated with poorer differentiation (P = 0.0303), higher pathological TNM stage (p = 0.0153) and poorer prognosis of adenocarcinoma patients (P = 0.0017). Multivariable analysis with Cox proportional hazards models confirmed that MUC5B expression increased the hazard of death after adjusting for other clinicopathological factors (HR = 2.66; 95%CI, 1.26–5.61). We also immunohistochemically evaluated TTF-1 expression and found that the combination of MUC5B with TTF-1 is a useful marker for adenocarcinomas. The diagnostic accuracies of TTF-1 and MUC5B for adenocarcinoma were 83.8% and 70.4%, respectively. The accuracy increased to 94.3% when the two factors were combined. In survival analysis, the MUC5B(High)/TTF-1(−) group was significantly associated with a poorer outcome compared with the MUC5B(Low)/TTF-1(+) group (p < 0.0001). The present study suggested that the combination of MUC5B and TTF-1 expression is useful for discriminating adenocarcinomas from squamous cell carcinomas, yielding prognostic significance in patients with lung adenocarcinoma.

Classification of lung cancer using ensemble-based feature selection and machine learning methods

Lung cancer is one of the leading causes of death worldwide. There are three major types of lung cancers, non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC) and carcinoid. NSCLC is further classified into lung adenocarcinoma (LADC), squamous cell lung cancer (SQCLC) as well as large cell lung cancer. Many previous studies demonstrated that DNA methylation has emerged as potential lung cancer-specific biomarkers. However, whether there exists a set of DNA methylation markers simultaneously distinguishing such three types of lung cancers remains elusive. In the present study, ROC (Receiving Operating Curve), RFs (Random Forests) and mRMR (Maximum Relevancy and Minimum Redundancy) were proposed to capture the unbiased, informative as well as compact molecular signatures followed by machine learning methods to classify LADC, SQCLC and SCLC. As a result, a panel of 16 DNA methylation markers exhibits an ideal classification power with an accuracy of 86.54%, 84.6% and a recall 84.37%, 85.5% in the leave-one-out cross-validation (LOOCV) and independent data set test experiments, respectively. Besides, comparison results indicate that ensemble-based feature selection methods outperform individual ones when combined with the incremental feature selection (IFS) strategy in terms of the informative and compact property of features. Taken together, results obtained suggest the effectiveness of the ensemble-based feature selection approach and the possible existence of a common panel of DNA methylation markers among such three types of lung cancer tissue, which would facilitate clinical diagnosis and treatment.

Spectrum of somatic EGFR, KRAS, BRAF, PTEN mutations and TTF-1 expression in Brazilian lung cancer patients

Lung cancer is the leading global cause of cancer-related mortality. Inter-individual variability in treatment response and prognosis has been associated with genetic polymorphisms in specific genes: EGFR, KRAS, BRAF, PTEN and TTF-1. Somatic mutations in EGFR and KRAS genes are reported at rates of 15-40% in non-small cell lung cancer (NSCLC) in ethnically diverse populations. BRAF and PTEN are commonly mutated genes in various cancer types, including NSCLC, with PTEN mutations exerting an effect on the therapeutic response of EGFR/AKT/PI3K pathway inhibitors. TTF-1 is expressed in approximately 80% of lung adenocarcinomas and its positivity correlates with higher prevalence of EGFR mutation in this cancer type. To determine molecular markers for lung cancer in Brazilian patients, the rate of the predominant EGFR, KRAS, BRAF and PTEN mutations, as well as TTF-1 expression, was assessed in 88 Brazilian NSCLC patients. EGFR exon 19 deletions (del746-750) were detected in 3/88 (3·4%) patients. Activating KRAS mutations in codons 12 and 61 were noted in five (5·7%) and two (2·3%) patients, respectively. None of the common somatic mutations were detected in either the BRAF or PTEN genes. TTF-1 was overexpressed in 40·7% of squamous-cell carcinoma (SCC). Our findings add to a growing body of data that highlights the genetic heterogeneity of the abnormal EGFR pathway in lung cancer among ethnically diverse populations.

Sebaceous-like clear cell changes in primary lung cancer

We examined two cases of primary lung cancer with sebaceous-like clear cells (SLCCs), defined as clear carcinoma cells with microvacuolated cytoplasm and centrally located nuclei, which were selected from among 281 surgical/autopsy cases of lung cancer (2/281, 0.7%). Both cases were higher stage (stage IIA and IIIA), and SLCCs were intermingled with adenocarcinoma cells of usual type. They showed minute mucin staining, no evidence of glycogen, diffuse positivity for epithelial membrane antigen and carcinoembryonic antigen, focal positivity for thyroid transcription factor-1, and negativity for Napsin A and gross cystic disease fluid protein-15. Oil red O stain and ultrastructural examination in both cases failed to reveal lipid in SLCCs. SLCCs could represent non-specific changes of lung adenocarcinoma with a relatively advanced stage, and should be discriminated from true sebaceous differentiation.

Neural lineage-specific homeoprotein BRN2 is directly involved in TTF1 expression in small-cell lung cancer

Thyroid transcription factor 1 (TTF1) plays crucial roles in thyroid, lung, and developing brain morphogenesis. Because TTF1-expressing neoplasms are generated from organs and tissues that normally express TTF1, such as the thyroid follicular epithelium and peripheral lung airway epithelium, TTF1 is widely used as a cell lineage-specific and diagnostic marker for thyroid carcinomas and for lung adenocarcinomas with terminal respiratory unit (TRU) differentiation. However, among lung neuroendocrine tumors, small-cell carcinomas (small-cell lung cancers (SCLCs)), most of which are generated from the central airway, also frequently express TTF1 at high levels. To clarify how SCLCs express TTF1, we investigated the molecular mechanisms of its expression using cultivated lung cancer cells and focusing upon neural cell-specific transcription factors. Both SCLC cells and lung adenocarcinoma cells predominantly expressed isoform 2 of TTF1, and TTF1 promoter assays in SCLC cells revealed that the crucial region for activation of the promoter, which is adjacent to the transcription start site of TTF1 isoform 2, has potent FOX-, LHX-, and BRN2-binding sites. Transfection experiments using expression vectors for FOXA1, FOXA2, LHX2, LHX6, and BRN2 showed that BRN2 substantially upregulated TTF1 expression, whereas FOXA1/2 weakly upregulated TTF1 expression. BRN2 and FOXA1/2 binding to the TTF1 promoter was confirmed through chromatin immunoprecipitation experiments, and TTF1 expression in SCLC cells was considerably downregulated after BRN2 knockdown. Furthermore, the TTF1 promoter in SCLC cells was scarcely methylated, and immunohistochemical examinations using a series of primary lung tumors indicated that TTF1 and BRN2 were coexpressed only in SCLC cells. These findings suggest that TTF1 expression in SCLC is a cell lineage-specific phenomenon that involves the developing neural cell-specific homeoprotein BRN2.

Two microRNA panels to discriminate three subtypes of lung carcinoma in bronchial brushing specimens

RATIONALE

Effective treatment for lung cancer requires accuracy in subclassification of carcinoma subtypes.

OBJECTIVES

To identify microRNAs in bronchial brushing specimens for discriminating small cell lung cancer (SCLC) from non-small cell lung cancer (NSCLC) and for further differentiating squamous cell carcinoma (SQ) from adenocarcinoma (AC).

METHODS

Microarrays were used to screen 723 microRNAs in laser-captured, microdissected cancer cells from 82 snap-frozen surgical lung specimens. Quantitative reverse-transcriptase polymerase chain reaction was performed on 153 macrodissected formalin-fixed, paraffin-embedded (FFPE) surgical lung specimens to evaluate seven microRNA candidates discovered from microarrays. Two microRNA panels were constructed on the basis of a training cohort (n = 85) and validated using an independent cohort (n = 68). The microRNA panels were applied as differentiators of SCLC from NSCLC and of SQ from AC in 207 bronchial brushing specimens.

MEASUREMENTS AND MAIN RESULTS

Two microRNA panels yielded high diagnostic accuracy in discriminating SCLC from NSCLC (miR-29a and miR-375; area under the curve [AUC], 0.991 and 0.982 for training and validation data set, respectively) and in differentiating SQ from AC (miR-205 and miR-34a; AUC, 0.977 and 0.982 for training and validation data set, respectively) in FFPE surgical lung specimens. Moreover, the microRNA panels accurately differentiated SCLC from NSCLC (AUC, 0.947) and SQ from AC (AUC, 0.962) in bronchial brushing specimens.

CONCLUSIONS

We found two microRNA panels that accurately discriminated between the three subtypes of lung carcinoma in bronchial brushing specimens. The identified microRNA panels may have considerable clinical value in differential diagnosis and optimizing treatment strategies based on lung cancer subtypes.

Classification of the four main types of lung cancer using a microRNA-based diagnostic assay

For patients with primary lung cancer, accurate determination of the tumor type significantly influences treatment decisions. However, techniques and methods for lung cancer typing lack standardization. In particular, owing to limited tumor sample amounts and the poor quality of some samples, the classification of primary lung cancers using small preoperative biopsy specimens presents a diagnostic challenge using current tools. We previously described a microRNA-based assay (miRview squamous; Rosetta Genomics Ltd., Rehovot, Israel) that accurately differentiates between squamous and nonsquamous non-small cell lung cancer. Herein, we describe the development and validation of an assay that differentiates between the four main types of lung cancer: squamous cell carcinoma, nonsquamous non-small cell lung cancer, carcinoid, and small cell carcinoma. The assay, miRview lung (Rosetta Genomics Ltd.), is based on the expression levels of eight microRNAs, measured using a sensitive quantitative RT-PCR platform. It was validated on an independent set of 451 samples, more than half of which were preoperative cytologic samples (fine-needle aspiration and bronchial brushing and washing). The assay returned a result for more than 90% of the samples with overall accuracy of 94% (95% CI, 91% to 96%), with similar performance observed in pathologic and cytologic samples. Thus, miRview lung is a simple and reliable diagnostic assay that offers an accurate and standardized classification tool for primary lung cancer using pathologic and cytologic samples.

Accurate classification of non-small cell lung carcinoma using a novel microRNA-based approach

PURPOSE

Advances in targeted lung cancer therapy now demand accurate classification of non-small cell lung cancer (NSCLC). MicroRNAs (miRNA) are recently discovered short, noncoding genes that play essential roles in tissue differentiation during normal development and tumorigenesis. For example, hsa-miR-205 is a miRNA that is highly expressed in lung squamous cell carcinomas (SqCC) but not in lung adenocarcinomas. The differential expression of miRNAs could be exploited to distinguish these tumor types.

EXPERIMENTAL DESIGN

One hundred and two resected NSCLCs were classified as SqCC or adenocarcinoma based on their histologic features and immunohistochemical profiles. Corresponding preoperative biopsies/aspirates that had been originally diagnosed as poorly differentiated NSCLCs were available for 21 cases. A quantitative reverse transcription-PCR diagnostic assay that measures the expression level of hsa-miR-205 was used to classify the carcinomas as SqCC or adenocarcinoma based solely on expression levels. The two sets of diagnoses were compared.

RESULTS

Using standard pathologic methods of classification (i.e., microscopy and immunohistochemistry), 52 resected lung carcinomas were classified as SqCCs and 50 as adenocarcinomas. There was 100% concordance between the diagnoses established by conventional and miRNA-based methods. MiRNA profiling also correctly classified 20 of the 21 preoperative biopsy specimens.

CONCLUSIONS

MiRNA profiling is a highly reliable strategy for classifying NSCLCs. Indeed, classification is consistently accurate even in small biopsies/aspirates of poorly differentiated tumors. Confirmation of its reliability across the full range of tumor grades and specimen types represents an important step toward broad application.

Prognostic relevance of TTF-1 and MMP-9 expression in advanced lung adenocarcinoma

BACKGROUND

The thyroid transcription factor-1 (TTF-1) is a tissue-specific transcription factor that could play an important role in cell differentiation and morphogenesis of lung tumors. Matrix metalloproteinase-9 (MMP-9) is a protease commonly expressed in non-small cell lung cancer, conferring angiogenic and metastatic potential.

METHODS

We assessed TTF-1 and MMP-9 tumor expression by immunohistochemistry in 51 patients with lung adenocarcinoma, stage IIIB or IV, treated with platinum regimens. A bicategorical prognostic model was obtained using the Kaplan-Meier method, Cox regression, and conjunctive consolidation.

RESULTS

The median expression of TTF-1 was 30.0% (range: 0-85.9%). All tumors expressed MMP-9 (median: 78.7%; range: 15.2-96.1%). Median survival was 41.6 weeks, with estimated 1- and 2-year survival rates of 45.0% and 22.0%, respectively. Poor performance status (Karnofsky scale) - hazards ratio (HR): 1.03, 95% confidence interval (CI): 1.01-1.06; low TTF-1 expression (<40%) - HR: 4.00, 95% CI: 1.75-9.09; and high MMP-9 expression (> or =80%) - HR: 2.82, 95% CI: 1.30-6.08 were independent prognostic factors. Patients could be stratified in three death risk groups according to markers expression: low risk (high TTF-1 and low MMP-9; median survival: 127.6 weeks), intermediate risk (low TTF-1 or high MMP-9; median survival: 39.0 weeks); and high risk (low TTF-1 and high MMP-9; median survival: 16.4 weeks).

CONCLUSION

TTF-1 and MMP-9 tumor expression as detected by immunohistochemistry may allow identification of different, clinically meaningful, prognostic groups of advanced lung adenocarcinoma patients treated with platinum regimens.