Lung adenocarcinoma with bronchioloalveolar carcinoma component is frequently associated with foci of high-grade atypical adenomatous hyperplasia

Precision therapy for cancer prevention by targeting carcinogenesis

Cancer represents a major global public health burden, with new cases estimated to increase from 14 million in 2012 to 24 million by 2035. Primary prevention is an effective strategy to reduce the costs associated with cancer burden. For example, measures to ban tobacco consumption have dramatically decreased lung cancer incidence and vaccination against human papillomavirus can prevent cervical cancer development. Unfortunately, the etiological factors of many cancer types are not completely clear or are difficult to actively control; therefore, the primary prevention of such cancers is not practical. In this review, we update the progress on precision therapy by targeting the whole carcinogenesis process, especially for three high-risk groups: (1) those with chronic inflammation, (2) those with inherited germline mutations, and (3) those with precancerous lesions like polyps, gastritis, actinic keratosis or dysplasia. We believe that attenuating chronic inflammation, treating precancerous lesions, and removing high-risk tissues harboring germline mutations are precision methods for cancer prevention.

Rationale for Lung Adenocarcinoma Prevention and Drug Development Based on Molecular Biology During Carcinogenesis

Lung adenocarcinoma (LUAD) is the most common and aggressive subtype of lung cancer with the greatest heterogeneity and aggression. Inspite of recent years’ achievements in understanding the pathogenesis of this disease, as well as the development of new therapeutic approaches, our knowledge on crucial early molecular events during its development is still rudimentary. Recent classification and grading of LUAD has postulated that LUAD does not arise spontaneously, but through a stepwise process from lung adenomatous premalignancy atypical adenomatous hyperplasia to adenocarcinoma in situ, minimally invasive adenocarcinoma, and eventually frankly invasive predominant adenocarcinoma. In this review, we discuss the molecular processes that drive the evolutionary process that results in the formation of LUAD. We also describe how to handle lung premalignancy in clinical settings based on the most recent advances in genomic biology and our own understanding of lung cancer prevention.

Expressions of ATF6, XBP1, and GRP78 in normal tissue, atypical adenomatous hyperplasia, and adenocarcinoma of the lung

Little is known about the association between the atypical adenomatous hyperplasia (AAH)-adenocarcinoma in situ sequence of the lung and endoplasmic reticulum-stress responders such as ATF6, XBP1, and GRP78. Using stored tissues, we examined (i) the percentage of a splicing form (active form) of XBP1 messenger RNA in normal lung tissue (NLT) and adenocarcinoma (ACA; using reverse-transcription polymerase chain reaction); (ii) ATF6 and GRP78 protein expressions in NLT and ACA (using Western blotting analysis); (iii) ATF6, XBP1, and GRP78 protein expressions in NLT, AAH, and ACA, including some adenocarcinoma in situ (using immunohistochemistry); and (iv) the incidence of nuclear translocation of the 3 proteins in these lesions. The percentage of the splicing form of XBP1 messenger RNA showed a borderline difference between NLT and ACA (P = .068). In the Western blotting analysis, the nuclear fractions of ATF6 (including the active form) and GRP78 proteins were higher in ACA than in NLT. In the immunohistochemistry, the values obtained for the incidence of the nuclear translocation of ATF6, XBP1, and GRP78 proteins were as follows, respectively: 13.3%, 2.2%, and 0.5% in low-grade AAH; 37.9%, 2.3%, and 2.2% in high-grade AAH; and 47.2%, 10.6%, and 4.4% in ACA. A significant difference was detected between low-grade AAH and ACA for ATF6. In terms of nuclear translocation, high-grade AAH seemed intermediate between low-grade AAH and ACA. These results support endoplasmic reticulum-stress responses, such as nuclear translocation of these 3 proteins (including their active forms), being in parallel with the progression of the adenoma-carcinoma sequence in the lung.

Glioblastoma and acute myeloid leukemia: malignancies with striking similarities

Acute myeloid leukemia (AML) and glioblastoma (GB) are two malignancies associated with high incidence of treatment refractoriness and generally, uniformly poor survival outcomes. While the former is a hematologic (i.e. a "liquid") malignancy and the latter a solid tumor, the two diseases share both clinical and biochemical characteristics. Both diseases exist predominantly in primary (de novo) forms, with only a small subset of each progressing from precursor disease states like the myelodysplastic syndromes or diffuse glioma. More importantly, the primary and secondary forms of each disease are characterized by common sets of mutations and gene expression abnormalities. The primary versions of AML and GB are characterized by aberrant RAS pathway, matrix metalloproteinase 9, and Bcl-2 expression, and their secondary counterparts share abnormalities in TP53, isocitrate dehydrogenase, ATRX, inhibitor of apoptosis proteins, and survivin that both influence the course of the diseases themselves and their progression from precursor disease. An understanding of these shared features is important, as it can be used to guide both the research about and treatment of each.

[Overview of Clinical Progress in Pulmonary Ground-glass Nodules]

磨玻璃结节（ground-glass nodules, GGNs）是肺结节中的特殊类型，随着高分辨薄层计算机断层扫描（high resolution computed tomography, HRCT）的应用，GGNs检出率逐年升高并受到日益广泛的关注。由于缺乏特征性临床症状，肺癌的早期诊断难度较大，而既往研究证实GGNs的出现常常提示与肺癌相关，因此加强筛查及管理有助于早期诊断及治疗肺癌。本文回顾既往相关研究，就GGNs的定义、分类、影像学特征、自然生长史、分子病理特征及诊治流程作一小结。

C4.4A as a biomarker in pulmonary adenocarcinoma and squamous cell carcinoma

The high prevalence and mortality of lung cancer, together with a poor 5-year survival of only approximately 15%, emphasize the need for prognostic and predictive factors to improve patient treatment. C4.4A, a member of the Ly6/uPAR family of membrane proteins, qualifies as such a potential informative biomarker in non-small cell lung cancer. Under normal physiological conditions, it is primarily expressed in suprabasal layers of stratified squamous epithelia. Consequently, it is absent from healthy bronchial and alveolar tissue, but nevertheless appears at early stages in the progression to invasive carcinomas of the lung, i.e., in bronchial hyperplasia/metaplasia and atypical adenomatous hyperplasia. In the stages leading to pulmonary squamous cell carcinoma, expression is sustained in dysplasia, carcinoma in situ and invasive carcinomas, and this pertains to the normal presence of C4.4A in squamous epithelium. In pulmonary adenocarcinomas, a fraction of cases is positive for C4.4A, which is surprising, given the origin of these carcinomas from mucin-producing and not squamous epithelium. Interestingly, this correlates with a highly compromised patient survival and a predominant solid tumor growth pattern. Circumstantial evidence suggests an inverse relationship between C4.4A and the tumor suppressor LKB1. This might provide a link to the prognostic impact of C4.4A in patients with adenocarcinomas of the lung and could potentially be exploited for predicting the efficacy of treatment targeting components of the LKB1 pathway.

Nodule characterization: subsolid nodules

In this review, we focus on the radiologic, clinical, and pathologic aspects primarily of solitary subsolid pulmonary nodules. Particular emphasis will be placed on the pathologic classification and correlative computed tomography (CT) features of adenocarcinoma of the lung. The capabilities of fluorodeoxyglucose positron emission tomography-CT and histologic sampling techniques, including CT-guided biopsy, endoscopic-guided biopsy, and surgical resection, are discussed. Finally, recently proposed management guidelines by the Fleischner Society and the American College of Chest Physicians are reviewed.

Diagnosis of lung adenocarcinoma in resected specimens: implications of the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification

A new lung adenocarcinoma classification has been published by the International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society. This new classification is needed to provide uniform terminology and diagnostic criteria, most especially for bronchioloalveolar carcinoma. It was developed by an international core panel of experts representing all 3 societies with oncologists/pulmonologists, pathologists, radiologists, molecular biologists, and thoracic surgeons.This summary focuses on the aspects of this classification that address resection specimens. The terms bronchioloalveolar carcinoma and mixed subtype adenocarcinoma are no longer used. For resection specimens, new concepts are introduced, such as adenocarcinoma in situ and minimally invasive adenocarcinoma for small solitary adenocarcinomas with either pure lepidic growth (adenocarcinoma in situ) and predominant lepidic growth with invasion of 5 mm or less (minimally invasive adenocarcinoma), to define the condition of patients who will have 100% or near 100% disease-specific survival, respectively, if they undergo complete lesion resection. Adenocarcinoma in situ and minimally invasive adenocarcinoma are usually nonmucinous, but rarely may be mucinous. Invasive adenocarcinomas are now classified by predominant pattern after using comprehensive histologic subtyping with lepidic (formerly most mixed subtype tumors with nonmucinous bronchioloalveolar carcinoma), acinar, papillary, and solid patterns; micropapillary is added as a new histologic subtype. Variants include invasive mucinous adenocarcinoma (formerly mucinous bronchioloalveolar carcinoma), colloid, fetal, and enteric adenocarcinoma.It is possible that this classification may impact the next revision of the TNM staging classification, with adjustment of the size T factor according to only the invasive component pathologically in adenocarcinomas with lepidic areas.

Subsolid pulmonary nodules: imaging evaluation and strategic management

PURPOSE OF REVIEW

Given the higher rate of malignancy of subsolid pulmonary nodules and the considerably lower growth rate of ground-glass nodules (GGNs), dedicated standardized guidelines for management of these nodules have been proposed, including long-term low-dose computed tomography (CT) follow-up (≥3 years). Physicians must be familiar with the strategic management of subsolid pulmonary nodules, and should be able to identify imaging features that suggest invasive adenocarcinoma requiring a more aggressive management.

RECENT FINDINGS

Low-dose CT screening studies for early detection of lung cancer have increased our knowledge of pulmonary nodules, and in particular our understanding of the strong although imperfect correlation of the subsolid pulmonary nodules, including pure GGNs and part-solid nodules, with the spectrum of preinvasive to invasive lung adenocarcinoma. Serial CT imaging has shown stepwise progression in a subset of these nodules, characterized by increase in size and density of pure GGNs and development of a solid component, the latter usually indicating invasive adenocarcinoma.

SUMMARY

There is close correlation between the CT features of subsolid nodules (SSNs) and the spectrum of lung adenocarcinoma. Standardized guidelines are suggested for management of SSNs.

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.

International association for the study of lung cancer/american thoracic society/european respiratory society international multidisciplinary classification of lung adenocarcinoma

INTRODUCTION

Adenocarcinoma is the most common histologic type of lung cancer. To address advances in oncology, molecular biology, pathology, radiology, and surgery of lung adenocarcinoma, an international multidisciplinary classification was sponsored by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society. This new adenocarcinoma classification is needed to provide uniform terminology and diagnostic criteria, especially for bronchioloalveolar carcinoma (BAC), the overall approach to small nonresection cancer specimens, and for multidisciplinary strategic management of tissue for molecular and immunohistochemical studies.

METHODS

An international core panel of experts representing all three societies was formed with oncologists/pulmonologists, pathologists, radiologists, molecular biologists, and thoracic surgeons. A systematic review was performed under the guidance of the American Thoracic Society Documents Development and Implementation Committee. The search strategy identified 11,368 citations of which 312 articles met specified eligibility criteria and were retrieved for full text review. A series of meetings were held to discuss the development of the new classification, to develop the recommendations, and to write the current document. Recommendations for key questions were graded by strength and quality of the evidence according to the Grades of Recommendation, Assessment, Development, and Evaluation approach.

RESULTS

The classification addresses both resection specimens, and small biopsies and cytology. The terms BAC and mixed subtype adenocarcinoma are no longer used. For resection specimens, new concepts are introduced such as adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) for small solitary adenocarcinomas with either pure lepidic growth (AIS) or predominant lepidic growth with ≤ 5 mm invasion (MIA) to define patients who, if they undergo complete resection, will have 100% or near 100% disease-specific survival, respectively. AIS and MIA are usually nonmucinous but rarely may be mucinous. Invasive adenocarcinomas are classified by predominant pattern after using comprehensive histologic subtyping with lepidic (formerly most mixed subtype tumors with nonmucinous BAC), acinar, papillary, and solid patterns; micropapillary is added as a new histologic subtype. Variants include invasive mucinous adenocarcinoma (formerly mucinous BAC), colloid, fetal, and enteric adenocarcinoma. This classification provides guidance for small biopsies and cytology specimens, as approximately 70% of lung cancers are diagnosed in such samples. Non-small cell lung carcinomas (NSCLCs), in patients with advanced-stage disease, are to be classified into more specific types such as adenocarcinoma or squamous cell carcinoma, whenever possible for several reasons: (1) adenocarcinoma or NSCLC not otherwise specified should be tested for epidermal growth factor receptor (EGFR) mutations as the presence of these mutations is predictive of responsiveness to EGFR tyrosine kinase inhibitors, (2) adenocarcinoma histology is a strong predictor for improved outcome with pemetrexed therapy compared with squamous cell carcinoma, and (3) potential life-threatening hemorrhage may occur in patients with squamous cell carcinoma who receive bevacizumab. If the tumor cannot be classified based on light microscopy alone, special studies such as immunohistochemistry and/or mucin stains should be applied to classify the tumor further. Use of the term NSCLC not otherwise specified should be minimized.

CONCLUSIONS

This new classification strategy is based on a multidisciplinary approach to diagnosis of lung adenocarcinoma that incorporates clinical, molecular, radiologic, and surgical issues, but it is primarily based on histology. This classification is intended to support clinical practice, and research investigation and clinical trials. As EGFR mutation is a validated predictive marker for response and progression-free survival with EGFR tyrosine kinase inhibitors in advanced lung adenocarcinoma, we recommend that patients with advanced adenocarcinomas be tested for EGFR mutation. This has implications for strategic management of tissue, particularly for small biopsies and cytology samples, to maximize high-quality tissue available for molecular studies. Potential impact for tumor, node, and metastasis staging include adjustment of the size T factor according to only the invasive component (1) pathologically in invasive tumors with lepidic areas or (2) radiologically by measuring the solid component of part-solid nodules.

Association of CYP19A1 polymorphisms with risks for atypical adenomatous hyperplasia and bronchioloalveolar carcinoma in the lungs

Estrogen has been indicated to play an etiological role in the development of lung adenocarcinoma (ADC), particularly bronchioloalveolar carcinoma (BAC), a type of ADC that develops from a benign adenomatous lesion, atypical adenomatous hyperplasia (AAH). Polymorphisms in the CYP19A1 gene cause interindividual differences in estrogen levels. Here, 13 CYP19A1 single-nucleotide polymorphisms (SNPs) were examined for associations with lung AAH risk. AAH is detected as ground-glass opacity (GGO) by computed tomography (CT) examination, and this study consisted of 100 individuals diagnosed with GGO in their lungs among 3088 CT-based cancer screening examinees and 424 without. Minor allele carriers for the rs3764221 SNP showed an elevated risk for GGO [odds ratio (OR) = 1.72, P = 0.017]. Associations of this SNP with risks for lung AAH and BAC in the lungs were next examined using 359 ADC cases whose resected lung lobes were subjected to a histological examination for AAH accompaniment and the presence of BAC components and 330 controls without cancer. The ORs were also increased for lung ADC accompanied by AAH (OR = 1.74, P = 0.029) as well as lung ADC with BAC components (OR = 1.41, P = 0.091). The minor allele was associated with an increased circulating estradiol level (P = 0.079) in a population of 363 postmenopausal women without cancer. These results indicate that CYP19A1 polymorphisms are involved in the risk for lung AAH and BAC in the lungs by causing differences in estrogen levels.

Small peripheral lung adenocarcinoma: clinicopathological features and surgical treatment

The clinical use of high-resolution computed tomography (CT) has greatly advanced diagnosis of small peripheral lesions of the lung. In CT images, these lesions often exhibit ground-glass opacity (GGO). Ground-glass opacity is typical of noninvasive bronchioloalveolar carcinoma (BAC), which is characterized by a lepidic pattern of cells that line the alveoli but do not invade neighboring structures. Bronchioloalveolar carcinoma is classified as a subset of lung adenocarcinoma, but has distinct clinical and pathological features and a favorable prognosis. Most small peripheral lung lesions, including BAC, probably originate in the epithelium of the peripheral airway. As with other subsets of non-small cell lung cancer, surgical resection is a potentially curative treatment. However, it is questionable whether a lobectomy is necessary for small lesions that exhibit GGO, particularly when they are <1 cm in diameter. Although several Japanese investigators have suggested that a limited resection, including a wedge resection and a segmentectomy without nodal dissection, is an appropriate treatment for small lung adenocarcinomas, this approach should be validated by clinical trials.

High-resolution computed tomography screening for lung cancer: unexpected findings and new controversies regarding adenocarcinogenesis

CONTEXT

Recent advances in human imaging technologies reawakened interest in lung cancer screening. Although historic and current preliminary and noncontrolled studies have not shown a decrease in lung cancer mortality in screened populations, many explanations have been proffered while the lung cancer community awaits the results of several large controlled population studies.

OBJECTIVE

To critically review the current model of adenocarcinoma development against the background of lung cancer screening results combined with observational pathologic and radiographic studies.

DATA SOURCES

Published articles pertaining to lung cancer screening, lung adenocarcinoma pathology, and radiology accessible through PubMed form the basis for this review.

CONCLUSIONS

The current adenocarcinogenesis model is probably valid for many but not all lung adenocarcinomas. Screening data combined with radiographic and pathologic studies suggest that not all lung adenocarcinomas are clinically aggressive, and it is uncertain whether all aggressive adenocarcinomas arise from identified precursors.

Association of KRAS polymorphisms with risk for lung adenocarcinoma accompanied by atypical adenomatous hyperplasias

The pulmonary adenoma susceptibility 1 (Pas1) gene affects susceptibility to the development of lung adenomas in mice with a subset of the adenomas progressing to adenocarcinoma (ADC). In this study, genotype distributions for 10 polymorphisms in the human counterparts for three mouse candidate Pas1 genes, KRAS, CASC1/LAS1 and LRMP, were examined in a hospital-based case-control study consisting of 364 lung ADC cases and 253 controls. All the ADC cases were subjected to lobectomy and subsequent pathological investigation of atypical adenomatous hyperplasia (AAH), a putative precursor for peripheral lung ADC, including bronchioloalveolar carcinoma, in the resected lobes. Eighty-one (22%) of the ADC cases carried at least one AAH lesion in addition to the primary ADC and 34 (9%) of them carried multiple AAH lesions. None of the 10 polymorphisms examined showed significant associations with overall lung ADC risk (P > 0.05). However, minor allele carriers for two polymorphisms in the KRAS gene, KRAS-1 and -6, showed significantly increased odds ratios (ORs) for ADC accompanied by multiple AAHs [OR = 3.0; 95% confidence interval (CI) = 1.4-6.2, P = 0.004 and OR = 2.4; 95% CI = 1.1-4.7, P = 0.02, respectively]. Minor haplotypes including the minor allele for the KRAS-6 polymorphism showed increased ORs for ADC accompanied by multiple AAHs, and KRAS transcripts from the minor allele for this polymorphism were more abundantly detected in lung tissues than those from the major allele. Thus, KRAS polymorphisms were indicated to be involved in risk for the development of AAHs that progress to ADC by causing differential KRAS oncogene expression in the lungs.

Lung cancer preneoplasia

From histological and biological perspectives, lung cancer is a complex neoplasm. Although the sequential preneoplastic changes have been defined for centrally arising squamous carcinomas of the lung, they have been poorly documented for the other major forms of lung cancers, including small cell lung carcinoma and adenocarcinomas. There are three main morphologic forms of preneoplastic lesions recognized in the lung: squamous dysplasias, atypical adenomatous hyperplasia, and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. However, these lesions account for the development of only a subset of lung cancers. Several studies have provided information regarding the molecular characterization of lung preneoplastic changes, especially for squamous cell carcinoma. These molecular changes have been detected in the histologically normal and abnormal respiratory epithelium of smokers. Two different molecular pathways have been detected in lung adenocarcinoma pathogenesis: smoking-associated activation of RAS signaling, and nonsmoking-associated activation of EGFR signaling; the latter is detected in histologically normal respiratory epithelium.

Open lobectomy for patients with stage I non-small cell lung cancer

Until additional multi-institutional, randomized, controlled trials provide evidence to the contrary, open lobectomy with mediastinal lymphadenectomy should be considered the gold standard for treating patients with stage I NSCLC with sufficient cardiopulmonary reserve, including older patients. It is the operation with which alternative pulmonary resections, including video-assisted thoracoscopic lobectomy and sublobar resection, should be compared. In treating stage I NSCLC patients, sublobar resection should be reserved for patients with inadequate physiologic reserve to tolerate lobectomy and for those enrolled in clinical trials.

Diagnosis and treatment of bronchioloalveolar carcinoma

PURPOSE OF REVIEW

Bronchioloalveolar carcinoma accounts for 5% of lung cancers, although histologically mixed bronchioloalveolar carcinoma and adenocarcinoma account for up to 20%. Bronchioloalveolar carcinoma histology is present in a majority of tumors found on lung-cancer screening by computed tomography. We review issues surrounding the diagnosis and treatment of bronchioloalveolar carcinoma, which often differs from other types of lung cancer.

RECENT FINDINGS

A spectrum of disease from histologically pure bronchioloalveolar carcinoma to adenocarcinoma exists. The approach to treatment of diseases within this spectrum is still evolving. Evidence on the role of sub-lobar resection, resection of multifocal disease, and pulmonary transplantation is reviewed. We also discuss epidermal growth factor receptor tyrosine kinase inhibitors, and their role in patients with bronchioloalveolar carcinoma.

SUMMARY

An understanding of recent developments in the diagnosis and treatment of patients with bronchioloalveolar carcinoma histology is important as early detection of lung cancer becomes more common. Ongoing clinical trials will provide important information on the role of limited resection. The use of epidermal growth factor receptor tyrosine kinase inhibitors should currently be limited to patients with advanced or recurrent disease who have failed cytotoxic chemotherapy. New targeted therapies are emerging for patients with bronchioloalveolar carcinoma histology.

Controversy about Small Peripheral Lung Adenocarcinomas: How Should We Manage Them?

In recent years, the clinical use of high-resolution computed tomography has greatly advanced the diagnosis of small lesions of the peripheral lung. Such small lesions are often associated with ground-glass opacity in computed tomography findings. The noninvasive bronchioloalveolar carcinoma component with a replacement growth pattern of alveolar lining cells manifests as ground-glass opacity. Bronchioloalveolar carcinoma is classified as a subset of lung adenocarcinoma, but has a distinct clinical presentation, tumor biology, and favorable prognosis. Most small peripheral lung lesions including bronchioloalveolar carcinoma putatively originate from the peripheral airway epithelium, in which the epidermal growth factor receptor gene is frequently mutated. As with other subsets of non-small cell lung cancer, surgical resection is a potentially curative treatment. For the ground-glass opacity type of tiny lesions, particularly those less than 1 cm in their greatest dimension, the question has been raised whether lobectomy is really needed. Although several authors in Japan suggest the suitability of limited resection including segmentectomy and wedge resection without any nodal dissections for these small lung adenocarcinomas, this procedure should be validated in future clinical trials.

Bronchioloalveolar carcinoma: a review

Bronchioloalveolar carcinoma (BAC) is classified as a subset of lung adenocarcinoma but has a distinct clinical presentation, tumor biology, response to therapy, and prognosis compared with other subtypes of non-small-cell lung carcinoma (NSCLC). Bronchioloalveolar carcinoma disproportionately affects women, never-smokers, and Asians and is characterized by growth along alveolar septae without evidence of stromal, vascular, or pleural invasion. Although pure BAC accounts for approximately 4% of lung cancers, tumors with histologically mixed BAC and adenocarcinoma account for > 20% of all NSCLCs, and the incidence of BAC might be increasing. Bronchioloalveolar carcinoma histology is most commonly found in small lesions identified incidentally on chest radiographs or computed tomography scans and might represent a precursor lesion to invasive adenocarcinoma. As with other subsets of NSCLC, surgical resection is the only potentially curative treatment. Patients with unresectable BAC are more likely to respond to the epidermal growth factor receptor tyrosine kinase inhibitors gefitinib and erlotinib than patients with other subtypes of NSCLC. Stage for stage, patients with BAC have a higher rate of long-term survival but might have an increased rate of intrathoracic recurrence than patients with other subtypes of NSCLC.

Chromosomal numerical abnormalities in early stage lung adenocarcinoma

Chromosomal numerical abnormalities (CNA) are ubiquitous in human cancers. However, the question of when a CNA occurs in the course of tumor generation and progression, is controversial. Recent radiological scrutiny has enabled the identification of small peripheral lesions in the lung. A chromosome-wide investigation encompassing almost all the chromosomal centromeres was performed using modified fluorescence in situ hybridization on the archived pathological samples of 16 atypical adenomatous hyperplasia (AAH) and 30 lung adenocarcioma (AdCa) specimens including those smaller than 1 cm in size. The prevalence of the gain was more extensive in male than in female patients, and in non-smokers than in smokers. It tended to be greater in poorly differentiated AdCa, in moderately differentiated AdCa, and in well-differentiated AdCa cases, in that order. Most AAH had non-specific gains affecting all the examined chromosomes. The prevalence of the gain differed significantly between AAH and bronchioloalveolar carcinoma (BAC) </= 1 cm, but not between BAC < 1 cm and well-differentiated AdCa > 1 cm. It is proposed that the CNA is a distinct phenomenon occurring in the early or premalignant stage of lung AdCa, and that the CNA itself may not be a sequel in the carcinogenetic process, but a driving factor in carcinogenesis.

Histological types and significance of bronchial epithelial dysplasia

Pulmonary epithelium is known to undergo a preneoplastic process prior to the development of lung carcinoma. Squamous dysplasia and atypical adenomatous hyperplasia have been identified and classified as preinvasive lesions of squamous cell carcinoma and peripheral pulmonary adenocarcinoma, respectively. However, these commonly recognized preinvasive lesions do not completely explain the development of all histological types of lung carcinoma. By examining 114 resection lung specimens, we concluded that there are four histological patterns of bronchial epithelial dysplasia based on morphological features (basal cell dysplasia, columnar cell dysplasia, bronchial epithelial dysplasia with transitional differentiation, and squamous dysplasia). The histological patterns were further characterized by immunohistochemistry. Basal cell dysplasia was focally positive for cytokeratin (CK) 17 and 10/13; columnar cell dysplasia was generally positive for CK7, 8, and 18; bronchial epithelial dysplasia with transitional differentiation had a heterogeneous immunoprofile, while squamous dysplasia was positive for CK10/13 and focally positive for CK17. Various degrees of abnormal expression of p53 and Ki-67 were found in the different types of bronchial epithelial dysplasia. The cases were divided into three groups based on degree and extent of bronchial epithelial dysplasia. By Crosstabs McNemar test, the Mann-Whitney U-test (for two independent groups), the Kruskal-Wallis one-way nonparametric ANOVA (for >2 independent groups) and Spearman correlation analysis, the degree and extent of bronchial epithelial dysplasia was shown to be positively correlated with the incidence of bronchogenic carcinoma and multifocal primary lung carcinoma (P<0.05). These findings indicated the following: (1) bronchial epithelium can develop various patterns of dysplasia with abnormal/ambiguous cell differentiation and abnormal expressions of p53 and Ki-67. Thus, these bronchial epithelial dysplastic lesions may represent a preneoplastic process. (2) The degree of bronchial epithelial dysplasia may significantly predispose individuals to bronchogenic carcinoma and multifocal primary lung carcinoma.

Platelet-derived growth factor-AA is an essential and autocrine regulator of vascular endothelial growth factor expression in non-small cell lung carcinomas

It is widely accepted that angiogenesis is required for tumor progression. Vascular endothelial growth factor (VEGF) is a key molecule for tumor angiogenesis; however, its expressional regulation is not well understood during all stages of tumorigenesis. Using cell lines and surgical specimens of human non-small cell lung cancers (NSCLCs), we here show that platelet-derived growth factor-AA (PDGF-AA) is an essential autocrine regulator for VEGF expression. To directly assess the expression of PDGF-AA-dependent VEGF and its roles in tumorigenesis, we stably transfected established cell lines with their antisense genes. In addition, the levels of PDGF-AA and VEGF expression in surgical sections were measured and compared with clinicopathologic findings such as tumor size and patient prognosis. PDGF-AA tightly regulated VEGF expression and had a greater effect on tumor size and patient prognosis than did VEGF in both cell lines and surgical sections. PDGF-AA expression was not seen in the atypical adenomatous hyperplasia at all, whereas VEGF was occasionally seen. Furthermore, the frequency of VEGF expression was higher in advanced NSCLCs than in precancerous lesions, which was tightly correspondent to the results for PDGF-AA. These results indicate that PDGF-AA is an important regulator of the frequency and level of VEGF expression during the transition from a precancerous lesion to advanced cancer. The PDGF-AA/VEGF axis, therefore, may be a ubiquitous autocrine system for enhancing angiogenic signals, and PDGF-AA, and its related pathways could be a more efficient target of antiangiogenic therapy for cancers than VEGF and its pathways.

Surgical treatments for multiple primary adenocarcinoma of the lung

BACKGROUND

The aim of this study was to identify the clinical characteristics of multiple primary adenocarcinomas and to evaluate the efficacy of surgical treatments.

METHODS

Three-hundred sixty-nine patients who underwent pulmonary resection for adenocarcinoma from January 1994 to December 2002 were reviewed.

RESULTS

Thirty-one patients (8.4%) were determined to have multiple primary adenocarcinomas that could be detected on chest x-rays or computed tomography (CT). Twenty-six patients were synchronous and five patients were metachronous with a median interval of 59.0 months. Forty-nine (72.1%) of the total 68 lesions exhibited ground-glass opacity on high-resolution CT (HRCT). Pathologically well-differentiated adenocarcinoma with mixed bronchioloalveolar pattern was the most common subtype (39.7%). Taking into consideration pulmonary function, size, location, and HRCT findings of the lesions the procedures performed were lobectomy with mediastinal lymph-node dissection for 32 patients, segmentectomy with hilar node dissection for 8 patients, and wedge resection for 28 patients. Of 17 patients with bilateral synchronous cancers, simultaneous bilateral pulmonary resection was performed in 14 patients including simultaneous bilateral video-assisted thoracic surgery (VATS) in 11 patients. After a median follow-up period of 27.7 months, the 3-year overall survival rate was 92.9% and the 3-year disease-free survival rates of synchronous cancer and metachronous cancer were 77.9% and 100%, respectively.

CONCLUSIONS

The incidence of multiple primary adenocarcinomas was relatively common. Early radiographic detection and surgical excision could yield a favorable prognosis. The use of VATS, even for synchronous bilateral patients, was a safe and beneficial procedure.

The utility of B72.3, carcinoembryonic antigen, and Leu M-1 in cell blocks

BACKGROUND

The distinction of bronchioloalveolar carcinoma (BAC) from atypical adenomatous hyperplasia (AAH) or reactive alveolar cell hyperplasia (RAH) can be difficult on aspiration cytology, even when cell block preparations are available. The authors evaluated the usefulness of B72.3, carcinoembryonic antigen (CEA), and Leu M-1 immunostains in differentiating BAC, AAH, and RAH.

METHODS

Immunostains for B72.3, CEA, and Leu M-1 were performed on cell block sections from 11 lung lesions that were diagnosed cytologically as BAC (6 lesions) and "atypical cells, cannot exclude BAC" (5 lesions). Ten histologic sections of AAH and 8 histologic sections of RAH also were stained.

RESULTS

Among the six lesions that had an unequivocal cytologic diagnosis of BAC, all sections were positive for two of three immunostains. Tissue follow-up confirmed BAC in all six lesions. Among the five lesions that were diagnosed as "atypical cells, cannot exclude BAC," four lesions were positive for two of three immunostains, and one lesion was negative for all three immunostains. Subsequent tissue follow-up confirmed BAC in four of these lesions. Follow-up histology of the wedge resection on the lesion in the atypical category that was negative for B72.3, CEA, and Leu M-1 showed only AAH. All 10 lesions that had a histologic diagnosis of AAH and 8 lesions that had a histologic diagnosis RAH were negative for B72.3, CEA, and Leu M-1.

CONCLUSIONS

Positive staining for at least 2 immunostains among B72.3, CEA, and Leu M-1 provided strong supportive evidence for the diagnosis of BAC, and a negative result for all 3 immunostains was helpful in excluding BAC and in differentiating BAC from AAH and RAH.

Current status of small peripheral adenocarcinomas of the lung and their importance to pathologists

There has been a large amount of work done recently on small peripheral stage I adenocarcinomas that come to resection. Radiological (including proportion of ground glass opacity) and pathological features of these lesions (predominant bronchioloalveolar component, central scar with or without invasion <0.5 cm) have been shown to be prognostically favorable with cure rate approaching 100% in some series. Most of these studies emanate from Japan. The relevance of these studies to other parts of the world, particularly North America, is discussed in light of the fact that some recent chemotherapeutic studies with gefitinib have shown increased response in individuals of Asian origin, suggesting that some genetic differences may be significant. The relevance of these findings to pathologists and the pathological study of small peripheral adenocarcinomas from elsewhere in the world are discussed.

Loss of expression of E-cadherin and beta-catenin is associated with progression of pulmonary adenocarcinoma

The aim of the present study was to determine the association of loss of membranous expression of epithelial (E)-cadherin and beta-catenin with the progression of pulmonary adenocarcinoma. The expression of E-cadherin and beta-catenin was examined in 154 cases of pulmonary adenocarcinoma, including 49 cases of atypical adenomatous hyperplasia (AAH), 40 cases of bronchioloalveolar carcinoma (BAC), 42 cases of BAC-dominant type of adenocarcinoma with mixed subtypes (early MX) and 23 cases of BAC-recessive type of adenocarcinoma with mixed subtypes (overt MX), by immunohistochemistry. E-cadherin expression was positive in all cases of AAH, in 37 cases (92.5%) of BAC and in 34 cases (81.0%) of early MX, while it was positive in three cases (13.0%) of overt MX. beta-Catenin expression was positive in 47 cases (95.9%) of AAH, in 28 cases (70%) of BAC, in 32 cases (76.2%) of early MX and in 11 cases (47.8%) of overt MX. The rates of expression of E-cadherin and beta-catenin among cases of AAH, BAC, early MX and overt MX were significantly reduced. Loss of expression of E-cadherin and beta-catenin may play an important role in the progression of pulmonary adenocarcinoma, and these events occur before structural destruction of the alveolar wall by invasion of carcinoma cell.

Correlation between computed tomographic findings, bronchioloalveolar carcinoma component, and biologic behavior of small-sized lung adenocarcinomas

OBJECTIVE

Differentiation of bronchioloalveolar carcinoma from other subtypes of lung adenocarcinomas is important in the preoperative assessment of patients. We examined the biologic aggressiveness of small-sized adenocarcinomas according to the pathologically defined bronchioloalveolar carcinoma degree and its correlation with computed tomography findings. In addition, we attempted to predict which patients were suitable for a lesser resection.

METHODS

Of 424 consecutive patients who underwent operation for primary lung cancer in the last 3 years, 114 with a histopathologically proven adenocarcinoma 3 cm or less in diameter underwent complete removal of the primary tumor. We examined the characteristics of patients classified into 3 groups based on the proportion of the bronchioloalveolar carcinoma component: 0% to 20% (n = 40), 21% to 50% (n = 38), and 51% to 100% (n = 36). We also investigated the correlation of the bronchioloalveolar carcinoma component with computed tomography findings such as ground-glass opacity (defined as a hazy increase on the lung window) and tumor shadow disappearance rate (defined as the ratio of the tumor area of the mediastinal window to that of the lung window).

RESULTS

Male gender (P =.0001), advanced pathologic stage (P =.001), larger size of the tumor (P =.004), nodal involvement (P =.04), pleural invasion (P =.0003), lymphatic invasion (P =.002), and vascular invasion (P =.0002) were observed more often among patients with a smaller proportion of bronchioloalveolar carcinoma. A positive and significant correlation was found between the rate of bronchioloalveolar carcinoma component and ground-glass opacity (R(2) = 0.488, P <.0001) and tumor shadow disappearance rate (R(2) = 0.727, P <.0001). As an independent predictor of nodal status, tumor shadow disappearance rate (P =.015) and bronchioloalveolar carcinoma component (P =.015), as well as tumor size, were significantly valuable, although ground-glass opacity proportion (P =.086) was marginally informative.

CONCLUSIONS

Small-sized adenocarcinomas with a greater ratio of bronchioloalveolar carcinoma component showed less aggressive behavior. Both tumor shadow disappearance rate and ground-glass opacity ratios, which are obtained preoperatively, were well associated with bronchioloalveolar carcinoma ratios, which are determined postoperatively. Furthermore, tumor shadow disappearance rate had a stronger impact as a predictor of bronchioloalveolar carcinoma component. Preoperative assessment of tumor shadow disappearance rate may be useful to identify patients requiring a less extensive pulmonary resection.

Is high-grade adenomatous hyperplasia an early bronchioloalveolar adenocarcinoma?

Atypical adenomatous hyperplasia (AAH) is a probable forerunner of bronchioloalveolar carcinoma (BAC) and pulmonary adenocarcinoma (AC) of mixed type. The present study analysed four low-grade AAHs, 13 high-grade AAHs, two BACs, nine mixed ACs, and one squamous cell carcinoma derived from 13 patients using comparative genomic hybridization. The average number of chromosomal aberrations was 1.2 in low-grade AAH, 9.6 in high-grade AAH, and 12.5 in AC. A high degree of overlap of genetic changes was found in high-grade AAH, BAC, and AC within individual patients. The high number of aberrations and the degree of shared aberrations found in high-grade AAH and AC raises questions about the separation of these two entities. In addition, in view of the monoclonal origin of multiple foci within the same patient, AAH may not be a precursor of AC in some cases, but rather may represent intraepithelial spread.