Clonal origin of multiple lung cancers: K-ras and p53 mutations determined by nonradioisotopic single-strand conformation polymorphism analysis

Synchronous Multiple Lung Cancers with Lymph Node Metastasis and Different EGFR Mutations: Intrapulmonary Metastasis or Multiple Primary Lung Cancers?

Background

There is no consensus on whether patients with synchronous multiple lung cancers (SMLC) who present with lymph node metastasis (LNM) but whose epidermal growth factor receptor (EGFR) mutations are different are considered to have intrapulmonary metastases or multiple primary lung cancers. Few studies on these patients have been reported.

Methods

The electronic medical records of patients with surgically resected multiple lung cancers between February 2016 and July 2019 were retrospectively reviewed, focusing on the clinical characteristics and prognosis of patients with LNM and different EGFR mutations.

Results

A total of 125 patients were diagnosed with SMLC, and only 8 patients had LNM and different EGFR mutations. Their mean age was 61.43 ± 8.08 years (range 47–69 years). EGFR detection suggested that 4 patients had completely different mutation types, and 4 patients had mutations in only 1 tumor. Only 1 of the 17 total lesions was squamous cell carcinoma, the rest were adenocarcinoma. All patients underwent adjuvant therapy after surgery. Except for 1 patient who underwent chemotherapy, the rest received tyrosine kinase inhibitor-targeted therapy. As at 15 October 2020, the average follow-up time was 28.68 ± 10.74 months (range 10.5–40.5 months), and all patients were alive except 1 who died from extensive pleural metastasis.

Conclusion

The current study highlights the clinical importance of EGFR detection in SMLC, especially in patients with LNM. SMLC with LNM and different EGFR mutations should be considered multiple primary lung cancers rather than intrapulmonary metastases, and comprehensive treatment based on surgery may be preferable in these patients due to a good prognosis.

Molecular profiling of key driver genes improves staging accuracy in multifocal non-small cell lung cancer

OBJECTIVE

Multifocal non-small cell lung cancer has historically been separated into synchronous primary lung cancers or intrapulmonary metastases with the use of histopathology. We hypothesize that using targeted next-generation sequencing of key driver mutations in multifocal non-small cell lung cancer will improve our ability to differentiate intrapulmonary metastases from synchronous primary lung cancers.

METHODS

We identified patients who underwent surgery for non-small cell lung cancer between 2013 and 2018 with multifocal tumors. Archived specimens were reviewed with a 4-gene next-generation sequencing panel identifying mutations of EGFR, KRAS, BRAF, and NRAS. Synchronous primary lung cancers were classified as lesions with different histopathologic subtypes or driver mutations. Tests of hypotheses were performed with the Fisher exact test. Calculations were performed in Stata (v13.0; StataCorp LLC, College Station, Tex).

RESULTS

A total of 18 patients had non-small cell lung cancer tumor specimens (n = 41) available from 2 or more sites. The pathologic diagnosis was predominantly adenocarcinoma (39/41 specimens). We detected a driver mutation in 68.3% (28/41) of all tumors. The most common mutations observed were in KRAS (n = 17/41) and EGFR (n = 7/41). Eleven patients had synchronous primary lung cancers, and 4 patients had intrapulmonary metastases based on combined histopathologic and molecular profiling results. Three lacked driver mutations in either lesion. Eight synchronous primary lung cancers (8/18, 44%) were downstaged when compared with their original diagnosis (P = .08). Of these, 4 patients received adjuvant chemotherapy unnecessarily in hindsight.

CONCLUSIONS

Molecular non-small cell lung cancer profiling using a 4-gene next-generation sequencing panel allows for better distinction between synchronous primary lung cancers and intrapulmonary metastases than histopathology alone. Routine use of next-generation sequencing for multifocal lesions prevents unnecessary adjuvant treatment for patients with histologically similar synchronous primary lung cancers.

Utility of Genomic Analysis in Differentiating Synchronous and Metachronous Lung Adenocarcinomas from Primary Adenocarcinomas with Intrapulmonary Metastasis

Distinguishing synchronous and metachronous primary lung adenocarcinomas from adenocarcinomas with intrapulmonary metastasis is essential for optimal patient management. In this study, multiple lung adenocarcinomas occurring in the same patient were evaluated using comprehensive histopathologic evaluation supplemented with molecular analysis. The cohort included 18 patients with a total of 52 lung adenocarcinomas. Eleven patients had a new diagnosis of multiple adenocarcinomas in the same lobe (n = 5) or different lobe (n = 6). Seven patients had a history of lung cancer and developed multiple new tumors. The final diagnosis was made in resection specimens (n = 49), fine needle aspiration (n = 2), and biopsy (n = 1). Adenocarcinomas were non‐mucinous, and histopathologic comparison of tumors was performed. All tumors save for one were subjected to ALK gene rearrangement testing and targeted Next Generation Sequencing (NGS). Using clinical, radiologic, and morphologic features, a confident conclusion favoring synchronous/metachronous or metastatic disease was made in 65% of patients. Cases that proved challenging included ones with more than three tumors showing overlapping growth patterns and lacking a predominant lepidic component. Genomic signatures unique to each tumor were helpful in determining the relationship of multiple carcinomas in 72% of patients. Collectively, morphologic and genomic data proved to be of greater value and achieved a conclusive diagnosis in 94% of patients. Assessment of the genomic profiles of multiple lung adenocarcinomas complements the histological findings, enabling a more comprehensive assessment of synchronous, metachronous, and metastatic lesions in most patients, thereby improving staging accuracy. Targeted NGS can identify genetic alterations with therapeutic implications.

Phenotype-genotype correlation in multiple primary lung cancer patients in China

Due to recent advances in high-resolution detection technology, multiple primary lung cancer (MPLC) is becoming an increasingly common diagnosis. However, the genotype-phenotype correlations in MPLC patients have not yet been assessed. In this study, we analyzed the clinical and pathological data for 129 consecutive MPLC patients who received curative surgery at the Tongji University Shanghai Pulmonary Hospital, China. We have screened 129 patients in the present study and found mutations in EGFR, BRAF, ROS1 and KRAS genes, as well as the rearrangement of the EML4-ALK gene in 113 patients. The mean patient age was 59.9 (25-78) years old and 41 patients were males (31.8%). Among the total patients, 123 (95.4%) had two primary lesions, 5 (3.9%) had three primary lesions, and 1 (0.8%) had four primary lesions. In 38.8% of the patients, all lesions were located on only one side of the body. Most of the detected mutations (98 patients) were in the EGFR gene. The patients exhibited significant differences in the EGFR mutation, age at diagnosis, and foci location.

Differential diagnosis between primary lung squamous cell carcinoma and pulmonary metastasis of head and neck squamous cell carcinoma

Differentiation between lung squamous cell carcinoma and pulmonary metastasis of head and neck squamous cell carcinoma is clinically important because the prognoses and therapeutic options are considerably different. However, the clinical, pathological, and immunohistochemical diagnostic methods have not yet been fully established. Although various molecular methods have been developed, they have not yet been practically applied. A combined approach involving molecular and immunohistochemical analysis, such as one that uses antibodies selected on the basis of comprehensive genetic analysis results, may be effective. We suggest a new diagnostic criteria using the clinical characteristics and the result of immunohistochemical analysis. However, there are two underlying problems in the development of new diagnostic methods: tumor heterogeneity and determination of the diagnostic accuracy.

"Different trend" in multiple primary lung cancer and intrapulmonary metastasis

Background

The distinguishing of intrapulmonary metastatic tumors from multiple primary lung cancers is difficult but of great importance for the therapeutic management and prognosis of these patients.

Methods

We used genomic DNA analyzed by six microsatellites (D7S1824, D15S822, D2S1363, D10S1239, D6S1056, and D22S689) with PCR to identify discordant allelic variation from 12 patients. There are five patients with multiple primary lung cancers and seven patients who were diagnosed with intrapulmonary metastases from 850 patients with primary lung cancer in our hospital. The experiments were approved by the West China Hospital Ethics committee (No. 2013 (33)) and all patients agreed to participate in the study and signed an informed consent form.

Results

In the group of metachronous lung tumor, three of five patients have different histological types and one of five patients have the same histological type which showed “contradictory trend”. The other one showed “unique trend”. In the second group (intrapulmonary metastasis lung tumor), one patient showed “contradictory trend” and the others showed “unique trend”.

Conclusions

“Different trends” are useful in discrimination of intrapulmonary metastasis lung cancer and multiple primary lung cancer even diagnosed with the histopathological evaluation.

A novel differential diagnostic model for multiple primary lung cancer: Differentially-expressed gene analysis of multiple primary lung cancer and intrapulmonary metastasis

The incidence of synchronous multiple primary lung cancer (MPLC) is increasing. However, present diagnostic methods are unable to satisfy the individualized treatment requirements of patients with MPLC. The present study aimed to establish a quantitative mathematical model and analyze its diagnostic value for distinguishing between MPLC and cases of the histologically similar disease, intrapulmonary metastasis (IPM). The sum value of the differential expression ratios of four proteins, namely p53, p16, p27 and c-erbB2, was evaluated by immunohistochemically-staining specimens of primary cancers, second separate cancers, metastatic lymph nodes and metastatic cancers. The sum value of the differential expression ratio of the four proteins from the primary tumor and the lymph-node metastasis or metastatic cancer was <90 in the 11 patients with a single metastatic cancer and in the 30 patients with lymph-node metastasis, but was >90 in the 14 patients with different histological types of MPLC. Therefore, a quantitative differentially-expressed gene mathematical model was established as follows: Sum of the differential expression ratios = p16T1 - T + p27T1 - T2 + C-erbB2T1 - T2 + p53T1 - T2, where T1 is the primary cancer and T2 is the lymph node metastasis, metastatic cancer or the second separate cancer. The quantitative differentially-expressed gene mathematical model is considered to be a useful tool for distinguishing between MPLC and IPM.

IASLC/ATS/ERS International Multidisciplinary Classification of Lung Adenocarcinoma: novel concepts and radiologic implications

In 2011, the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society proposed a new classification for lung adenocarcinoma that included a number of changes to previous classifications. This classification now considers resection specimens, small biopsies, and cytology specimens. Two former histopathologic terms, bronchioloalveolar carcinoma and mixed subtype adenocarcinoma, are no longer to be used. For resection specimens, the new terms of adenocarcinoma in situ and minimally invasive adenocarcinoma are introduced for small adenocarcinomas showing pure lepidic growth and predominantly lepidic growth, with invasion ≤5 mm, respectively. Invasive adenocarcinomas are now classified by their predominant pattern as lepidic, acinar, papillary, and solid; a micropapillary pattern is newly added. This classification also provides guidance for small biopsies and cytology specimens. For adenocarcinomas that include both an invasive and a lepidic component, it is suggested that for T staging the size of the T-factor may be best measured on the basis of the size of the invasive component rather than on the total size of tumors including lepidic components, both on pathologic and computed tomography assessment. This suggestion awaits confirmation in clinical-radiologic trials. An implication for M staging is that comprehensive histologic subtyping along with other histologic and molecular features can be very helpful in determining whether multiple pulmonary nodules are separate primaries or intrapulmonary metastases. In this review article, we provide an illustrated overview of the proposed new classification for lung adenocarcinoma with an emphasis upon what the radiologist needs to know in order to successfully contribute to the multidisciplinary strategic management of patients with this common histologic subtype of lung cancer.

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.

Epidermal growth factor receptor mutation and pathologic-radiologic correlation between multiple lung nodules with ground-glass opacity differentiates multicentric origin from intrapulmonary spread

INTRODUCTION

No standard guidelines detailing recommendations for the selection and treatment for multiple lung nodules with ground-glass opacity (GGO) have been established. For treatment decision, we analyzed epidermal growth factor receptor (EGFR)/K-ras somatic aberrations and pathologic-radiologic correlation in multiple lung nodules presented as GGO to differentiate multifocal lesions from intrapulmonary spread.

METHODS

Twenty-four patients with multiple lung nodules presented as GGO were identified to investigate somatic mutations of EGFR (exon 18-21) and K-ras (codons 2, 13, and 61). This series included 18 atypical adenomatous hyperplasias (AAH), 15 bronchioloalveolar carcinomas (BAC), and 23 adenocarcinomas (ADC) obtained from 24 patients.

RESULTS

High frequency of discordant EGFR mutations (17 of 24, 70.8%) could discriminate tumor clonality (18 of 24, 75%) of multiple lung neoplastic nodules presented as GGO. EGFR mutations were common in AAH (38.9%), BAC (46.7%), and ADC (39.1%). In case 4, AAH and BAC had different mutational changes, and in case 10, the BAC lesion contains EGFR mutation that is not in the invasive ADC. In case 17, the BAC had more mutational changes than the carcinoma. The pure GGO appearance in the radiologic examination corresponded preinvasive pathologic change.

CONCLUSIONS

This study showed that synchronous BAC and/or ADC can have different EGFR or K-ras mutational profiles suggesting these lesions arise as independent events rather than intrapulmonary spread or systemic metastasis. This has significant implication in staging and treatment. These findings might be a clue to establish guidelines of the multiple neoplastic lung nodules with GGO.

Testing clonal relatedness of tumors using array comparative genomic hybridization: a statistical challenge

In recent years several investigative groups have sought to use array technologies that characterize somatic alterations in tumors, such as array comparative genomic hybridization (ACGH), to classify pairs of tumors from the same patients as either independent primary cancers or metastases. A wide variety of strategies have been proposed. Several groups have endeavored to use hierarchical clustering for this purpose. This technique was popularized in genomics as a means of finding clusters of patients with similar gene expression patterns with a view to finding subcategories of tumors with distinct clinical characteristics. Unfortunately, this method is not well suited to the problem of classifying individual pairs of tumors as either clonal or independent. In this article we show why hierarchical clustering is unsuitable for this purpose, and why this method has the paradoxical property of producing a declining probability that clonal tumor pairs will be correctly identified as more information is accrued (i.e., more patients). We discuss alternative strategies that have been proposed, which are based on more conventional conceptual formulations for statistical testing and diagnosis, and point to the remaining challenges in constructing valid and robust techniques for this problem.

Use of epidermal growth factor receptor/Kirsten rat sarcoma 2 viral oncogene homolog mutation testing to define clonal relationships among multiple lung adenocarcinomas: comparison with clinical guidelines

BACKGROUND

The incidence of multiple lung adenocarcinomas is rising, making it difficult to determine the stage and assign treatment in an increasing number of patients following surgery. Clinical guidelines have been developed to distinguish independent non-small cell lung cancers from metastases, that is, criteria developed by Martini and Melamed and the American College of Chest Physicians (ACCP). However, these guidelines can be difficult to apply and may give conflicting results. Here, we report on seven patients in whom epidermal growth factor receptor (EGFR) and Kirsten-rat sarcoma 2 viral oncogene homolog (KRAS) tumor mutation status was used to determine clonal relationships among multiple lung lesions.

METHODS

We identified seven patients whose paired lung adenocarcinomas were found to harbor distinct EGFR or KRAS mutations. We assessed these patients' disease status using established clinical guidelines. We also explored the use of comprehensive histologic subtyping (CHS) of tumor sections to distinguish multiple primaries.

RESULTS

According to the Martini-Melamed criteria, six of the seven patients had multiple primary lung tumors. By ACCP criteria, three patients had multiple primaries, and three patients had metastases. Classification of the seventh patient by ACCP criteria was indeterminate. Mutational testing suggested that all paired tumors were multiple primary adenocarcinomas, which was consistent with results from CHS.

CONCLUSIONS

Assuming that independent tumor clones harbor distinct mutations, these seven cases highlight discrepancies between the existing clinical criteria used to distinguish independent tumor foci from metastases. EGFR/KRAS mutation testing of multiple lung adenocarcinomas can assist in differentiating multiple primary lung adenocarcinomas from metastatic lesions. Use of CHS in this setting should also be further explored.

Evaluation of the clonal origin of multiple primary melanomas using molecular profiling

Numerous investigations have been conducted using molecular profiling to evaluate the possible clonal origin of second malignancies in various cancer types. However, to date no study assessing clonality of multiple primaries has been conducted in melanoma. In this investigation using patients treated at a specialist melanoma treatment center, we compared the somatic mutational profiles of pairs of melanomas designated as independent on the basis of thorough assessment of their clinical and pathologic characteristics. We used a set of highly polymorphic genetic markers selected on the basis of their chromosomal positions and the frequencies of reported allelic losses at these genetic loci. Our statistical testing strategy showed no significant evidence of clonal origin of the two primaries in 17 of the 19 patients examined. The results suggest that most second melanomas designated as independent primary tumors on the basis of their clinicopathologic features are indeed independent occurrences of the disease, supporting the validity of the criteria used by experienced pathologists in distinguishing new primaries from metastases.

Three different synchronous primary lung tumours: A case report with extensive genetic analysis and review of the literature

Synchronous triple lung tumours are rare and little is known as for their genetic basis. Here we report a case of a 59 years old male with three synchronous independent and histological different primary tumours of the left lung. Two nodules were located in the upper lobe and consisted of an adenocarcinoma (ADC) and an endobronchial poorly differentiated squamous cell carcinoma (SCC). A third nodule of the lower lobe corresponded to a small cell neuroendocrine carcinoma (SCLC). To assess if they represented independent primary tumours and have common genetic profiles, tumours were investigated for loss of heterozygosity (LOH) at 40 chromosomal markers. A comparable fractional allelic loss of 0.52 was observed in the ADC and SCLC, while it was 0.28 in the SCC. Microallelotyping analysis did not reveal a common genetic profile, supporting the hypothesis that the three synchronous tumours are truly independent primaries with different histogenesis.

Clonality and prognostic implications of p53 and epidermal growth factor receptor somatic aberrations in multiple primary lung cancers

PURPOSE

For treatment decision and prognostic applications, we evaluated p53/epidermal growth factor receptor (EGFR) somatic aberrations in multiple primary lung cancers to differentiate multifocal tumors from intrapulmonary metastasis.

EXPERIMENTAL DESIGN

Fifty-eight multiple primary lung cancers of 1,037 patients in a 10-year period were identified to investigate somatic mutations and altered expression of p53 and EGFR for clonality assessment. Genomic DNA was extracted from microdissected cells of paraffin-embedded multiple primary lung cancer tissues. Overexpression and somatic mutations in exons of p53 (exons 5-8) and tyrosine kinase domain of EGFR (exons 18-22) were examined by immunohistochemical staining and DNA sequencing, respectively.

RESULTS

High frequency of somatic mutations in p53 (33 of 58, 56.9%) and/or EGFR (44 of 58, 75.9%) resulted in high discrimination rate of tumor clonality (50 of 58, 86.2%) of multiple primary lung cancers. Twenty-two cases (37.9%) were assessed as having the same clonality and 28 cases (48.3%) were determined as having different clonality, which further supported the carcinogenic theory of field cancerization. Notably, the occurrence of lymph node metastasis was more commonly observed in tumors with the same clonality (P = 0.045) and was associated with poor patient 5-year survival rate (P = 0.001). However, no correlation was found between tumor clonality and patient survival (P = 0.630). The EGFR somatic aberrations in 58 multiple primary lung cancers, including vascular invasion associated with EGFR overexpression (P = 0.012) and mutation (P = 0.025), further suggested the potential benefits of target therapy of inoperable multiple primary lung cancers.

CONCLUSIONS

Our results suggest that analysis of somatic alterations in p53 and EGFR can significantly improve the clonality assessment and impact management of multiple primary lung cancer patients.

Synchronous multiple primary lung cancers with different response to gefitinib

Synchronous bronchiolo-alveolar cell carcinoma (BAC) in both lungs and squamous cell carcinoma in left lung were found in a 66-year-old male smoker. After two courses of chemotherapy with gemcitabine and carboplatin, the left lung mass had partially resolved, however, the extent of BAC had been increased. When gefitinib was used as a second-line chemotherapy, the consolidation lesions of BAC was improved while the mass of squamous cell carcinoma was aggravated. The analysis of epidermal growth factor receptor-tyrosine kinase (EGFR-TK) mutations showed that BAC had the deletion, delE746-A750 in exon 19, however, squamous cell carcinoma had no mutations. These synchronous tumors with different location, histology, status of EGFR-TK mutations and response to chemotherapy might be caused by different molecular pathogenesis.

Patterns of allelic loss of synchronous adenocarcinomas of the lung

Distinction of multiple primary lung carcinomas from intrapulmonary metastases using empiric clinical and histopathologic criteria can be difficult. Recent advances have provided several molecular markers that can be used for clonal analysis of separate tumor nodules and enhance tumor staging and subsequent treatment and prognosis. To address this issue, we performed a microdissection-based allelotyping of 20 cases of histologically similar, pathologic stage T4 adenocarcinomas (ADCs). Loss of heterozygosity (LOH) analysis included a panel of 15 polymorphic microsatellite markers located on 1p, 3p, 5q, 9p, 9q, 10q, 17p, and 22q. The tumor size, visceral pleural and angiolymphatic invasion, lymph node status, outcome, and survival were assessed. Allelotypes of 60 cases of solitary primary non-small cell lung carcinomas (NSCLC) (stages I-II) were used to define the percentage of discordant LOH patterns within solitary primary lung carcinoma that would discriminate between survivors and nonsurvivors. These criteria were used in the analysis of pathologic stage T4 ADC. Two groups of stage T4 cases were created: molecularly homogenous (< or = 40% discordances) (14 cases, 70%), and molecularly heterogenous (>40% discordances) (6 cases, 30%). Molecularly homogenous tumors were more frequently associated with visceral pleural invasion (92% vs. 8%) (P = 0.018). Allelotype did not correlate with age, gender, tumor size, tumor differentiation, lymph node status, angiolymphatic invasion, survival, or outcome. Our study showed that discordant and concordant genotypic profiles exist in morphologically similar synchronous ADC of the lung.

Determination of the molecular relationship between multiple tumors within one patient is of clinical importance

PURPOSE

To determine the molecular relationship between multiple tumors within one patient and to evaluate the impact of this knowledge on clinical management.

PATIENTS AND METHODS

In 25 consecutive patients with multiple tumors, proven by histology and immunohistochemistry to be identical, molecular aberrations were determined. Each patient had at least one lesion in the lung or head and neck region. Loss of heterozygosity (LOH) and p53 aberration analyses were carried out, and similar aberration profiles suggest clonality and metastasis whereas different profiles suggest independent primary tumors.

RESULTS

The molecular determinations indicated that 12 patients had a probable second primary tumor and 10 patients had a metastasis of the first lesion. In three patients, both an independent primary tumor and a metastasis were present. The molecular findings determined the course of additional treatment in all 10 patients with metastases, in all three patients with both a second primary tumor and a metastasis, and in seven of 12 patients with a second primary tumor.

CONCLUSION

By comparing DNA alterations of multiple tumors within one patient, the relationship between the tumors can be assessed. This study shows that in 20 of 25 patients, knowledge of the nature of both lesions was essential in clinical decision making. Furthermore, after thorough analysis of the five cases where clinical decision making was not influenced, there was in retrospect no clear indication for LOH or p53 analysis. Because these molecular analyses can be performed on routine specimens, they can be applied in almost all patients.

PCR techniques for clonality assays

Clonal overgrowths represent the hallmark of neoplastic proliferations, and their demonstration has been proved useful clinically for the diagnosis of malignant lymphomas based on the detection of specific and dominant immunoglobulin and/or T-cell receptor gene rearrangements. Nonrandom genetic alterations can also be used to test clonal expansions and the clonal evolution of neoplasms, especially analyzing hypervariable deoxyribonucleic acid (DNA) regions from patients heterozygous for a given marker. These tests rely basically on the demonstration of loss of heterozygosity (LOH) resulting from either hemizygosity (nonrandom interstitial DNA deletions) or homozygosity of mutant alleles observed in neoplasms. LOH analyses identify clonal expansions of a tumor cell population, and point to monoclonal proliferation when multiple and consistent LOH are demonstrated. Based on the methylation-related inactivation of one X chromosome in female subjects, X-linked markers (e.g., androgen receptor gene) will provide clonality information using LOH analyses after DNA digestion with methylation-sensitive restriction endonucleases. Therefore, both non-X-linked and X-linked analyses give complementary information, related and not related to the malignant transformation pathway respectively. Applied appropriately, these tools can establish the clonal evolution of tumor cell populations (tumor heterogeneity), identify early relapses, distinguish recurrent tumors from other metachronic neoplasms, and differentiate field transformation from metastatic tumor growths in synchronic and histologically identical neoplasms.

Expression and regulation of a molecular marker, SPR1, in multistep bronchial carcinogenesis

A small proline-rich protein, SPR1, is overexpressed in squamous metaplasia of bronchial epithelium. We studied the expression and regulation of SPR1 in a series of human bronchial epithelial cell lines representing a model of multistep bronchial carcinogenesis. These cell lines included a primary culture of tracheobronchial epithelial cells (HTBE), a papilloma virus-transformed tracheobronchial epithelial cell line (HBE1), a cell line selected from HBE1 by a tobacco carcinogen and a phorbol ester (HBE1-C), a simian virus-transformed bronchial epithelial cell line (BEAS-2B), and a lung carcinoma cell line (H460). Different tumorigenic potentials of these cell lines were indicated by graded levels of telomerase activity. Concomitant with squamous transformation, there was an increase in SPR1 expression in HTBE, HBE1, and HBE1-C that was reversible by vitamin A. With progression of tumorigenicity, there was a marked reduction in SPR1 expression in BEAS-2B and a total loss of expression in H460. In these latter cell lines representing advanced malignant transformation, there was a loss of up- and downregulation, respectively, by the phorbol ester and vitamin A. Transfection study with chimeric constructs of the SPR1 promoter and a reporter gene showed that the dysregulation of SPR1 expression in malignant transformation was a result of perturbation of the basal and enhancer elements of the first 162 nucleotides in the 5'-flanking promoter region of the SPR1 gene. These findings suggest an association of transcriptional dysregulation of the SPR1 gene with multistep bronchial carcinogenesis.