The clinical behavior of "mixed" small cell/large cell bronchogenic carcinoma compared to "pure" small cell subtypes

Efficacy of Tyrosine Kinase Inhibitors in Primary Driver-Gene-Positive Combined Small-Cell Lung Cancer: A Retrospective Study

BACKGROUND

Combined small-cell lung cancer (c-SCLC) with gene mutations is a rare subtype often found alongside adenocarcinoma. Targeted therapy may be effective because of the presence of specific molecular targets. However, due to its rarity and unconventional genetic testing, the efficacy remains uncertain.

METHODS

A total of 31 c-SCLC patients with gene mutations were retrospectively included and grouped according to their treatment regimens. Treatment outcomes were evaluated. Kaplan-Meier method was used for survival analysis, with Log Rank test applied for comparison between groups.

RESULTS

We divided the 31 patients into 3 groups according to first-line treatment: group A (chemotherapy, n = 16), group B (targeted monotherapy, n = 7), and group C (targeted combination therapy, n = 8). The overall response rates (ORR) were 43.8%, 42.9%, and 62.5%. The disease control rates (DCR) were 87.5%, 85.7%, and 100%. The median progression-free survival (PFS) was 4.0, 5.0, and 7.93 months (P = .024), with a significant difference between group A and C (P = .010). The median overall survival (OS) was 14.10, 17.43, and 12.93 months (P = .313). Seven patients in group A received targeted therapy in later-line. Of the total 22 patients received targeted monotherapy or combination therapy, the ORR and DCR were 54.5% and 90.9%. The median PFS and OS were 5.87 and 17.30 months. Additionally, adverse events (AEs) occurred in 53.8% and 88.9% of monotherapy and combination therapy. The most common AEs in monotherapy were elevated transaminases (23.1%) and in combination anemia (66.7%).

CONCLUSIONS

TKIs showed encouraging efficacy in driver-gene-positive c-SCLC. While monotherapy may be a supplementary option, combination with chemotherapy appears to be preferable and superior.

Molecular subtype expression and genomic profiling differ between surgically resected pure and combined small cell lung carcinoma

A new molecular subtype classification method has been proposed for small cell lung carcinoma (SCLC). However, little is known about the differences between the pure (P-SCLC) and combined subtypes (C-SCLC). We aimed to compare the molecular subtype expression and genomic profiling in terms of clinical relevance between the two groups. 154 surgically resected SCLCs were analyzed for protein expression of four subtypes (ASCL1, NEUROD1, POU2F3, and YAP1) and two predictive markers (DLL3 and MYC) by immunohistochemistry (IHC). We also performed whole exome sequencing of 60 samples to examine genomic profiles. A total of 113 patients with P-SCLC and 41 with C-SCLC were included. In P-SCLC and C-SCLC, the expression of these markers was 78.8% and 41.5%, 98.2% and 97.6%, 42.5% and 51.2%, 38.9% and 85.4%, 85.0% and 68.3%, and 24.8% and 34.1%, respectively. ASCL1 and DLL3 were highly expressed in P-SCLC (p = 0.000 and p = 0.021, respectively), and YAP1 expression was significantly enriched in C-SCLC (p = 0.000). NGS results, including 45 P-SCLCs and 15 C-SCLCs, indicated that EGFR gene mutations were mostly observed in C-SCLCs (p = 0.000). C-SCLC showed higher CNA burden and wGII than P-SCLC (p < 0.01 and p < 0.05); conversely, P-SCLC had higher TMB burden and SDI (p < 0.05 and p < 0.05). YAP1 expression was associated with poor prognosis in P-SCLC but with favorable prognosis in C-SCLC. P-SCLC and C-SCLC are heterogeneous diseases characterized by different molecular subtype expressions and genomic profiles. Our data provide a basis for adopting histological subtype-based treatments, and further prospective studies are required to confirm our conclusions.

Rare Combined Small Cell Lung Carcinoma and Lung Squamous Cell Carcinoma Response to PD-1 Inhibitor as Third-Line Therapy: A Case Report

Background

Combined small cell lung cancer (c-SCLC) is a relatively rare subtype of SCLC, especially when SCLC is initially diagnosed and recurrent lesions are non-small cell lung cancer (NSCLC). Moreover, SCLC combined lung squamous cell carcinoma (LUSC) has few been reported.

Case Presentation

Here, we report a 68-year-old man pathologically diagnosed as stage IV SCLC of right lung. With cisplatin and etoposide, the lesions were significantly reduced. It was not until three years later that a new lesion was found in his left lung, pathologically confirmed as LUSC. The patient was initiated with sintilimab based on high tumor mutational burden (TMB-H). Both lung tumors were stable, and PFS was 9.7 months.

Conclusion

This case provides a meaningful reference for the third-line treatment of SCLC combined LUCS patients. This case also provides valuable information on the response to PD-1 inhibition of patients with c-SCLC based on TMB-H and better understanding of PD-1 therapy applications in the future.

Killing SCLC: insights into how to target a shapeshifting tumor

Small cell lung cancer (SCLC) is a rapidly growing, highly metastatic, and relatively immune-cold lung cancer subtype. Historically viewed in the laboratory and clinic as a single disease, new discoveries suggest that SCLC comprises multiple molecular subsets. Expression of MYC family members and lineage-related transcription factors ASCL1, NEUROD1, and POU2F3 (and, in some studies, YAP1) define unique molecular states that have been associated with distinct responses to a variety of therapies. However, SCLC tumors exhibit a high degree of intratumoral heterogeneity, with recent studies suggesting the existence of tumor cell plasticity and phenotypic switching between subtype states. While SCLC plasticity is correlated with, and likely drives, therapeutic resistance, the mechanisms underlying this plasticity are still largely unknown. Subtype states are also associated with immune-related gene expression, which likely impacts response to immune checkpoint blockade and may reveal novel targets for alternative immunotherapeutic approaches. In this review, we synthesize recent discoveries on the mechanisms of SCLC plasticity and how these processes may impinge on antitumor immunity.

Clinicopathological Difference and Survival Impact of Patients with c-SCLC and SCLC

Background

Combined small cell lung cancer (c-SCLC) distinguishes itself from small cell lung cancer (SCLC) due to its inclusion of both SCLC and non-small cell lung cancer (NSCLC) components. Few studies have compared clinicopathological characteristics, prognosis and factors affecting survival. We therefore addressed the issues in this study.

Patients and Methods

A total of 400 c-SCLC and 20,841 SCLC patients were enrolled using SEER database. Difference in clinicopathological characteristics of SCLC and c-SCLC patients was analyzed using chi-square. Kaplan–Meier was applied to compare their survival before and after propensity score matching (PSM). Cox regression model was adopted to assess the impact of different clinical variables on survival. Logistic regression was applied to identify risk factors for c-SCLC and SCLC patients.

Results

Differences in race, sex, T stage, N stage, surgery, bone, brain and liver metastasis were detected between c-SCLC and SCLC patients. c-SCLC patients had better overall survival (OS) than SCLC patients before PSM. Age, race, sex, T stage, N stage, surgery, bone, brain, liver and lung metastasis were prognostic factors affecting OS for c-SCLC and SCLC (P < 0.05). However, a significant OS benefit was not observed in c-SCLC after adjusting for clinicopathological variables (HR, 0.950; 95% CI, 0.842–1.073; P=0.411). No significant OS difference was found between c-SCLC and SCLC patients after PSM (P = 0.789). c-SCLC patients had lower risk of lymph node (OR: 0.555; 95% CI: 0.439–0.703; P < 0.001) and liver metastasis (OR: 0.591; 95% CI: 0.448–0.779; P < 0.001), whereas had no significant differences in bone and brain metastasis risks (P > 0.05) compared with SCLC patients.

Conclusion

The prognosis of c-SCLC did not significantly differ from that of SCLC if clinicopathological characteristics are controlled. Better prognosis for c-SCLC patients over SCLC patients may be ascribed to fewer liver and lymph node metastases upon diagnosis.

YAP1 protein expression has variant prognostic significance in small cell lung cancer (SCLC) stratified by histological subtypes

BACKGROUND

Recently, expression of YAP1, a nuclear effector of an inactivated HIPPO pathway, has been identified as one of four molecular subtypes of SCLC. However, the clinicopathological relevance and prognostic significance of YAP1 expression in SCLC stratified by histological subtypes has not been systematically reported to date.

METHODS

Tumor sections and corresponding formalin-fixed paraffin-embedded (FFPE) samples of 297 SCLC patients were retrieved from the pathological specimen repository and were subsequently reviewed by pathologists. Forty-six C-SCLCs (combined SCLCs) (15.5%) and 251P-SCLCs (pure SCLCs) (84.5%) were identified respectively. YAP1 expression was examined by immunohistochemistry (IHC) and assessed semi-quantitatively on tumor tissue array (TMA). Propensity score was used to match C-SCLCs and P-SCLCs in a ratio of 1 to 2 to balance age, gender, tumor stage and treatment methods. Finally, 46C-SCLCs and 92P-SCLCs were included for prognostic analysis.

RESULTS

The positive rate of YAP1 expression was significantly higher in C-SCLCs than P-SCLCs before matching (52.2% vs 29.1%, P = 0.004). After matching by propensity score, the prescribed clinical parameters were well balanced between P-SCLCs and C-SCLCs. Expression of YAP1 was associated worse overall survival (OS) (5- year OS%, 39.0% vs. 74.9%, P = 0.013) and was an independent risk factor for OS (HR = 2.93, 95% CI: 1.01-8.51; P = 0.048) exclusively in C-SCLC. Univariate survival analysis in subgroups of different clinical variables also confirmed the prognostic impact of YAP1 was most significant in C-SCLC. But for P-SCLCs, expression of YAP1 showed no prognostic impact.

CONCLUSIONS

Expression of YAP1 in small cell components of C-SCLC was significantly higher than that in P-SCLC. Besides, it served as an unfavorable predictor for OS in C-SCLC but not in P-SCLC, which suggested different entities of small cell components with variant YAP1 expression and potential different targetable oncogenic pathway between C-SCLC and P-SCLC.

National Cancer Database report of nonmetastatic esophageal small cell carcinoma

Background

Esophageal small cell carcinoma (ESCC) is a rare malignancy for which there is no consensus management approach. This is the largest known analysis of nonmetastatic ESCC patients to date, evaluating national practice patterns and outcomes of surgical‐based therapy vs chemoradiotherapy (CRT) vs chemotherapy alone.

Methods

The National Cancer Data Base was queried for esophageal cancer patients with histologically confirmed nonmetastatic ESCC. Univariable and multivariable logistic regression ascertained factors associated with receipt of surgical‐based management. Kaplan‐Meier analysis evaluated overall survival (OS) and the log‐rank test is used to compare OS between groups; Cox univariate and multivariate analyses determined variables associated with OS.

Results

Altogether, 323 patients were analyzed; 64 (20%) patients underwent surgical‐based therapy, 211 (65%) CRT, and 48 (15%) chemotherapy alone. On multivariable analysis, no single factor significantly predicted for administration of surgery. Despite no OS differences between the surgery‐based (median OS 21 months) and CRT arms (18 months), both were superior to CT alone (10 months) (P < 0.001). Among other factors, receiving any local therapy independently predicted for higher OS over chemotherapy alone on Cox multivariate analysis (P < 0.001).

Conclusions

This study of a large, contemporary national database demonstrates that most ESCC is treated with CRT in the United States; adding local therapy to systemic therapy may be beneficial to these patients, although individualized multidisciplinary management is still recommended.

Combined Small Cell Carcinoma of the Lung: Is It a Single Entity?

BACKGROUND

SCLC accounts for 15% and 20% of all lung cancers, with combined SCLC (CSCLC) comprising 2% to 5%. Little is known about the clinical characteristics and molecular changes associated with the various histologic components.

METHODS

A total of 205 SCLC cases were resected between 2005 and 2015. Clinical and pathologic features were analyzed. All CSCLC cases were confirmed by histologic examination and immunohistochemistry. The individual components were microdissected using a novel automated dissection system, and DNA was extracted and subjected to targeted exome sequencing.

RESULTS

A total of 10 cases of CSCLC were identified out of 170 cases with adequate histologic material; squamous cell carcinoma comprised the second component in half of these (n = 5). There were no significant differences between CSCLC and pure SCLC with respect to clinical features. The median follow-up time was 36 months. The median survival times of patients with pure SCLC and CSCLC were 58 months and 26 months, respectively (p = 0.030). The different components of three cases of CSCLC were deemed adequate for microdissection and sequencing. Approximately 75% of the identified somatic mutations were present in both components. There were also 15 gene mutations or six amplifications unique to only one of the components.

CONCLUSIONS

We identified no significant clinical or pathologic differences between pure SCLC and CSCLC; CSCLC was associated with decreased overall survival compared with pure SCLC. The histologic components of CSCLC had high genetic concordance but also showed divergent genotypes. These findings may suggest a common precursor with subsequent acquisition of oncogenic changes in CSCLC.

Clinical outcomes of surgically resected combined small cell lung cancer: a two-institutional experience

BACKGROUND

The combined small cell lung cancer (c-SCLC) was rare and its clinicopathological characteristics had not been thoroughly described. The aim of this study was to determine prognostic factors and survival in c-SCLC patients.

METHODS

Clinical records of patients with c-SCLC who underwent surgery between January 2009 and December 2013 in two institutions were retrospectively reviewed.

RESULTS

Ninety-seven patients were identified. The most common pathology was combined SCLC and large cell neuroendocrine carcinoma (LCNEC, N=46), followed by combined SCLC and squamous cell carcinoma (SCC) (N=32), combined SCLC and adenocarcinoma (AC) (N=12), and combined SCLC and adenosquamous carcinoma (ASC) (N=7). The overall survival (OS) rates of the entire cohort were 42.4% and 35.2% at 3 and 5 years, respectively. Multivariate analysis identified sex [female vs. male, hazards ratio (HR) =0.38; 95% confidence interval (CI): 0.19-0.79; P=0.010], age (<53 vs. >53 years, HR =0.28; 95% CI: 0.09-0.81; P=0.019), performance status (<2 vs. >2, HR =0.08; 95% CI: 0.02-0.32; P<0.001), combined non-small cell lung cancer (NSCLC) components (LCNEC vs. non-LCNEC, HR =3.00; 95% CI: 1.03-8.76; P=0.045), adjuvant therapy (yes vs. no, HR =0.33; 95% CI: 0.17-0.67; P=0.002) as significantly prognostic factors of OS in patients with complete resection and lymphadenectomy.

CONCLUSIONS

The mixed NSCLC components within c-SCLCs had a significant influence on the survival. Compared with surgery alone, adjuvant therapy was associated with significantly improved survival in patients with complete resection and lymphadenectomy.

High pretreatment neutrophil-lymphocyte ratio predicts recurrence and poor prognosis for combined small cell lung cancer

BACKGROUNDS

Compared to pure small cell lung cancer (SCLC), combined small cell lung cancer (C-SCLC) has its own characteristics. High neutrophil to lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) have been shown to be related to poor prognosis in several types of tumors. The aim of this study was to explore the prognosis value of NLR and PLR in patients with C-SCLC.

METHODS

A total of 112 patients diagnosed with C-SCLC between January 2000 and March 2009 were enrolled in the study. The clinicopathological parameters, laboratory analyses, and survival time were collected and analyzed. The correlation between NLR, PLR, and clinicopathological characters was analyzed. Univariate and multivariate analyses were performed to investigate the prognostic significance of these parameters for C-SCLC.

RESULTS

The pretreatment NLR was elevated in 37.5 % patients (NLR ≥ 4.15; n = 42; H-NLR). NLR was significantly related to disease stage (p = 0.033) and tumor recurrence (p = 0.014). The median overall survival (OS) and progression-free survival (PFS) were significantly worse in the H-NLR group (OS: 22.0 months vs 11.7 months, p = 0.001; PFS: 11.1 vs 6.0 months, p < 0.001). However, PLR at diagnosis was not associated with OS or PFS. Multivariate analyses indicated elevated NLR (HR = 1.6; p = 0.001), disease stage (HR = 1.6; p = 0.001), and performance status (HR = 1.8; p = 0.015) as independent prognostic factors.

CONCLUSIONS

High pretreatment NLR (≥4.15) is a potential useful indicator for C-SCLC recurrence and predicts a poor long-term prognosis for C-SCLC, which should be considered in defining the prognosis with other well-known prognosticators in C-SCLC patients.

Elevated RABEX-5 protein expression predicts poor prognosis in combined small cell lung cancer

RABEX-5 has been studied in various solid tumors, but its role in combined small cell lung cancer (C-SCLC) remains unknown. This study aimed to investigate the expression, the potential relevance to clinicopathological characters and prognostic significance of RABEX-5 in patients with C-SCLC. Fifty-two C-SCLC patients who received radical surgery were enrolled in our study. The clinicalpathological data and survival time were reviewed. The mRNA and protein expression of RABEX-5 from the paired tumor tissues and adjacent normal tissues were determined, and its relationship with clinicalpathological variables and prognosis was analyzed. Univariate and multivariate analyses were performed to investigate the prognostic significance of RABEX-5 for C-SCLC. The mRNA and protein expression level of RABEX-5 was significantly elevated in C-SCLC tissues. The increased RABEX-5 protein expression was correlated with clinical stage (p = 0.011) and tumor recurrence (p = 0.006). The median OS and DFS was significantly shorter in the high RABEX-5 expression group compared to low RABEX-5 expression group (OS: 12.0 vs. 21.7 months, p = 0.014; DFS: 6.7 vs. 11.8 months, p = 0.005). Multivariate Cox analysis indicated that high RABEX-5 protein expression was an independent prognostic factor for OS and DFS (p < 0.001). RABEX-5 is a potential useful indicator and predicts a poor long-term prognosis for C-SCLC, which should be considered in defining the prognosis with other well-known prognosticators in C-SCLC patients.

Combined small-cell lung carcinoma: An institutional experience

BACKGROUND

The purpose of this study is to determine prognostic factors and survival in patients who present with combined small-cell lung cancer (SCLC).

METHODS

A retrospective review of combined SCLC histology in patients treated between1995-2010 was undertaken. Demographics, diagnostic information, disease characteristics, treatment modality, and survival were captured. Survival estimates were performed using Kaplan Meier analysis. Statistical significance was defined as P < 0.05.

RESULTS

Forty-one patients were identified, and 35 records were available for analysis. Median age at diagnosis was 68 (range 50-85). The study included 20 (57%) women and 15 (43%) men; and 94% had a current or former history of smoking. Histology was SCLC/large cell carcinoma not otherwise specified in 28 (80%), and SCLC/adenocarcinoma or SCLC/squamous cell carcinoma in seven (20%). Cardiac or pulmonary comorbidities were present in 80% of patients, and 24 patients had metastatic disease at presentation. Twenty-eight patients received treatment of chemotherapy (n = 24), cranial radiotherapy (n = 5), or thoracic radiotherapy (n = 7). Staging was as follows: stage I-III (n = 11), stage IV (n = 24). Median survival was 15.4 months (range <1-53 months) and 3.4 months (range <1-21.9 months) for American Joint Committee on Cancer (AJCC) stage I-III and stage IV, respectively. Estimated overall six and 12 month survival was 82%, 55%, 37%, and 17% for stage I-III and stage IV, respectively. An improved overall survival rate was found for patients with an Eastern Cooperative Oncology Group performance status of <2, and no weight loss (P < 0.05).

CONCLUSION

Akin to SCLC, advanced stage combined SCLC portends a poor prognosis. Perhaps novel chemotherapeutic drugs or targeted agents may improve outcomes for future patient populations.

Selective tropism of Seneca Valley virus for variant subtype small cell lung cancer

We assessed the efficacy of Seneca Valley virus (SVV-001), a neuroendocrine cancer-selective oncolytic picornavirus, in primary heterotransplant mouse models of small cell lung cancer (SCLC), including three lines each of classic and variant SCLC. Half-maximal effective concentrations for cell lines derived from three variant heterotransplants ranged from 1.6×10(-3) (95% confidence interval [CI] = 1×10(-3) to 2.5×10(-3)) to 3.9×10(-3) (95% CI = 2.8×10(-3) to 5.5×10(-3)). Sustained tumor growth inhibition in vivo was only observed in variant lines (two-sided Student t test, P < .005 for each). Doses of 10(14) vp/kg were able to completely and durably eradicate tumors in a variant SCLC heterotransplant model in two of six mice. Gene expression profiling revealed that permissive lines are typified by lower expression of the early neurogenic transcription factor ASCL1 and, conversely, by higher expression of the late neurogenic transcription factor NEUROD1. This classifier demonstrates a sensitivity of .89, specificity of .92, and accuracy of .91. The NEUROD1 to ASCL1 ratio may serve as a predictive biomarker of SVV-001 efficacy.

NeuroD1 regulates survival and migration of neuroendocrine lung carcinomas via signaling molecules TrkB and NCAM

Small-cell lung cancer and other aggressive neuroendocrine cancers are often associated with early dissemination and frequent metastases. We demonstrate that neurogenic differentiation 1 (NeuroD1) is a regulatory hub securing cross talk among survival and migratory-inducing signaling pathways in neuroendocrine lung carcinomas. We find that NeuroD1 promotes tumor cell survival and metastasis in aggressive neuroendocrine lung tumors through regulation of the receptor tyrosine kinase tropomyosin-related kinase B (TrkB). Like TrkB, the prometastatic signaling molecule neural cell adhesion molecule (NCAM) is a downstream target of NeuroD1, whose impaired expression mirrors loss of NeuroD1. TrkB and NCAM may be therapeutic targets for aggressive neuroendocrine cancers that express NeuroD1.

Combined SCLC clinical and pathologic characteristics

INTRODUCTION

Despite the well characterized clinical course of 'pure' SCLC, there have not been many data on combined SCLC, ie, tumors, which contain both small-cell and non-small-cell components.

MATERIALS AND METHODS

We analyzed 1628 consecutive cases of lung cancer (1200 NSCLC, 428 SCLC) at our institution over the past decade. We identified 22 patients with C-SCLC. The pathologic and clinical characteristics of these patients were reviewed. Survival analysis was performed and prognostic factors were assessed. These data were compared with the results obtained from our 406 pure SCLC patients who presented during the same time period.

RESULTS

The most common pathology was combined small-cell and large-cell with 16 cases followed by combined small- and squamous-cell carcinoma (3 cases), 2 cases of small-cell and nonspecified NSCLC, and 1 case of small cell and adenocarcinoma. Overall survival was significantly higher in C-SCLC patients compared with pure SCLC (median 15 vs. 10.8 months; P = .035). Surgery was significantly more common in this group of patients (45% vs. 3% in the pure small cell group; P < .0001). No difference in overall survival was observed in patients with C-SCLC and patients with pure SCLC, that did not receive surgery (P = .64).

CONCLUSION

Patients with combined SCLC carry a better prognosis than those with pure small-cell variety and are more likely to undergo surgery.

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.

Neuroendocrine tumors of the lung: an update

CONTEXT

The 2004 World Health Organization (WHO) classification recognizes 4 major types of lung neuroendocrine tumors: typical carcinoid, atypical carcinoid, small cell lung cancer, and large cell neuroendocrine carcinoma. Markedly different prognostic implications and treatment paradigms for these tumors underscore the importance of accurate pathologic diagnosis.

OBJECTIVE

To detail the clinical and pathologic features of lung neuroendocrine tumors, with emphasis on diagnostic criteria, differential diagnoses, and application of immunohistochemistry. The emerging evidence for the utility of Ki-67 (MIB1) in the diagnosis of lung neuroendocrine tumors, particularly in small biopsy and cytology, is emphasized.

DATA SOURCES

The 2004 WHO classification, other published literature, and primary material from the author's institution.

CONCLUSIONS

The current WHO classification of neuroendocrine tumors is based on morphologic features in combination with precisely defined mitotic rate and absence or presence of necrosis. Ki-67 (MIB1) is emerging as a useful ancillary tool in the diagnosis of these tumors. Continued research efforts are needed to identify additional immunohistochemical and molecular biomarkers that can serve as ancillary diagnostic tools and as potential therapeutic targets for these diseases.

Combined small cell lung carcinomas: genotypic and immunophenotypic analysis of the separate morphologic components

Combined small cell lung carcinomas (CSCLCs) are small cell lung carcinomas (SCLCs) containing discrete areas of non-small cell morphologic components, found in up to 30% of SCLCs. We assessed immunophenotypic and genotypic similarity between the distinct morphologic constituents in 7 CSCLCs. Each was stained for synaptophysin, CD56, chromogranin, bcl-2, thyroid transcription factor (TTF)-1, cytokeratin 7, and PAX-5. Loss of heterozygosity (LOH) analysis was performed using markers on 3p (2 loci), 17p (3 loci), 17q (1 locus), and 22q (2 loci). The distinct components shared an identical immunophenotype in 6 cases; all were positive for synaptophysin and CD56 in both components. LOH analysis revealed shared loss of least 1 marker in every lesion, including LOH at 22q13 (characteristic of SCLC) in 5 tumors. The individual elements constituting CSCLCs are closely related in most cases despite their distinct morphologic appearances. The prevalent expression of synaptophysin and CD56 and loss of 22q13 suggest that these tumors are biologically closer to SCLC.

Arsenic trioxide is highly cytotoxic to small cell lung carcinoma cells

Small cell lung carcinoma (SCLC) is an extremely aggressive form of cancer and current treatment protocols are insufficient. SCLC have neuroendocrine characteristics and show phenotypical similarities to the childhood tumor neuroblastoma. As multidrug-resistant neuroblastoma cells are highly sensitive to arsenic trioxide (As2O3) in vitro and in vivo, we here studied the cytotoxic effects of As2O3 on SCLC cells. As2O3 induced pronounced cell death in SCLC cells at clinically relevant concentrations, and also at hypoxia. SCLC cells were more sensitive than non-SCLC cells to As2O3. Cell death was mainly due to necrosis, although apoptotic responses were also seen. A significant in vivo effect of As2O3 on SCLC growth was shown in a nude mice-xenograft model, although a fraction of the treated tumor-bearing animals did not respond. The nonresponding SCLC tumors differed in morphology and cell organization compared with treatment-responsive tumors, which in turn, showed decreased vascularization and higher expression of neuroendocrine markers compared with control tumors. Our results suggest a potential clinical application of As2O3 in SCLC therapy. In addition to cell death induction, antiangiogenic induction of differentiation may also be part of the in vivo effect of As2O3 on SCLC growth, as suggested by an increase in neuroendocrine markers in cultured cells.

Neuroendocrine carcinomas of the lung: a critical analysis

Neuroendocrine carcinomas represent an important group of primary neoplasms in the lung. During the last decades, the nomenclature of these tumors has evolved and the current use of immunohistochemical and molecular biology studies have, to some extent, expanded the conventional view of these tumors. However, the primary diagnosis of most of these lesions is performed on limited biopsy specimens, which may not translate well when one is confronted with a nomenclature that is based on resected material. In addition, for some of these specific entities, some confusion and controversy apparently remain, allowing for the proliferations of different terms that, although they may be dismissed as "semantics," may have a role in interpretation, further subclassification, and, possibly, treatment. Herein we review current concepts regarding the classification of these neoplasms and the role of this classification in our daily practice and discuss how it may impact treatment.

Inhibition of the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin pathway but not the MEK/ERK pathway attenuates laminin-mediated small cell lung cancer cellular survival and resistance to imatinib mesylate or chemotherapy

The fact that small cell lung cancer (SCLC) is commonly incurable despite being initially responsive to chemotherapy, combined with disappointing results from a recent SCLC clinical trial with imatinib, has intensified efforts to identify mechanisms of SCLC resistance. Adhesion to extracellular matrix (ECM) is one mechanism that can increase therapeutic resistance in SCLC cells. To address whether adhesion to ECM increases resistance through modulation of signaling pathways, a series of SCLC cell lines were plated on various ECM components, and activation of two signaling pathways that promote cellular survival, the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway and the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) pathway, was assessed. Although differential activation was observed, adhesion to laminin increased Akt activation, increased cellular survival after serum starvation, and caused the cells to assume a flattened, epithelial morphology. Inhibitors of the PI3K/Akt/mTOR pathway (LY294002, rapamycin) but not the MEK/ERK pathway (U0126) abrogated laminin-mediated survival. SCLC cells plated on laminin were not only resistant to serum starvation-induced apoptosis but were also resistant to apoptosis caused by imatinib. Combining imatinib with LY294002 or rapamycin but not U0126 caused greater than additive increases in apoptosis compared with apoptosis caused by the inhibitor or imatinib alone. Similar results were observed when adenoviruses expressing mutant Akt were combined with imatinib, or when LY294002 was combined with cisplatin or etoposide. These studies identify laminin-mediated activation of the PI3K/Akt/mTOR pathway as a mechanism of cellular survival and therapeutic resistance in SCLC cells and suggest that inhibition of the PI3K/Akt/mTOR pathway is one strategy to overcome SCLC resistance mediated by ECM.

Current perspectives in cancer proteomics

Proteome technology has been used widely in cancer research and is a useful tool for the identification of new cancer markers and treatment-related changes in cancer. This article details the use of proteome technology in cancer research, and laboratory-based and clinical cancer research studies are described. New developments in proteome technology that enable higher sample-throughput are evaluated and methods for enhancing conventional proteome analysis (based on two-dimensional electrophoresis) discussed. The need to couple laboratory-based proteomics research with clinically relevant models of the disease is also considered, as this remains the next main challenge of cancer-related proteome research.

In vitro chemo- and radio-resistance in small cell lung cancer correlates with cell adhesion and constitutive activation of AKT and MAP kinase pathways

Most small cell lung cancer (SCLC) patients relapse within 12 months of starting combination chemotherapy plus radio-therapy, due to the development of acquired chemo- and radio-resistance. This phenomenon relates to the induction of tumour differentiation, resulting in apoptosis-resistant, morphologically variant (v-SCLC) cells, which lack the neuroendocrine expression of classic (c-) SCLC cells. In this study spontaneously adherent SCLC sublines were shown by differential gene expression analysis to provide an in vitro model of variant differentiation in SCLC, with down-regulation of neuroendocrine markers and up-regulation of epithelial differentiation markers cyclin D1, endothelin, the cell adhesion molecules CD 44 and integrin subunits alpha2, beta3 and beta4. The sensitivity of adherent SCLC sublines to etoposide, cyclophosphamide and gamma radiation was significantly diminished relative to parent suspension cell lines. Western blot analysis using phosphorylation-specific antibodies to Akt and MAP kinase revealed markedly elevated activation in adherent SCLC sublines, paralleled by increased levels of phosphorylated Bad protein and activated NF-kappaB. Subcultivation of the adherent sublines on uncoated surfaces reversed their adherent phenotype immediately and under these conditions Akt activity reverted to low levels. These results suggest that c-SCLC cells can differentiate spontaneously to v-SCLC and that the associated cellular adhesion may trigger Akt-dependent inhibition of apoptosis in SCLC cells, thus leading to acquired chemo- and radio-resistance.

Small cell lung carcinoma (SCLC): a clinicopathologic study of 100 cases with surgical specimens

Separation of small cell lung carcinoma (SCLC) from nonsmall cell lung carcinoma (NSCLC) is a critical distinction to be made in the diagnosis of lung cancer. However, the diagnosis of SCLC is most commonly made on small biopsies and cytologic specimens, and practicing pathologists may not be familiar with all its morphologic guises and frequent combination with NSCLC elements, which may be seen in larger specimens. Following the most recent WHO classification of lung tumors and with the hope of identifying prognostic markers, we examined in detail the histology of 100 surgical biopsies or resections with a diagnosis of SCLC from the AFIP and pathology panel of the International Association for the Study of Lung Cancer (IASLC). Multiple clinical and histologic features were studied by Kaplan-Meier analysis. Neuroendocrine architectural patterns, including nested and trabecular growth, with peripheral palisading and rosette formation were common in SCLC. Necrosis and apoptotic debris was prominent in all cases, but crush artifact was infrequent. Cell size in surgical biopsy specimens appears larger than in bronchoscopic biopsy specimens and occasional cells may show prominent nucleoli and vesicular nuclear chromatin, but this does not preclude the diagnosis of SCLC. A high percentage of cases (28%) showed combinations with NSCLC, with large cell carcinoma the most common, followed by adenocarcinoma and squamous cell carcinoma. Because of the frequency of a few scattered large cells in SCLC, we arbitrarily recommend that at least 10% of the tumor show large cell carcinoma before subclassification as combined SC/LC. However, combined SCLC is easily recognized if the additional component consists of other NSCLC subtypes such as adenocarcinoma or squamous cell carcinoma, so no percentage requirement is needed. Stage remained the only predictor of prognosis.

The solitary pulmonary nodule: a primer on differential diagnosis

Despite significant advances in noninvasive imaging techniques, management of the solitary pulmonary nodule (SPN) remains a challenge for chest physicians. Patients with SPNs are frequently asymptomatic, and the physical examination is seldom revealing. Accurate diagnosis is essential, because >50% of patients will require prompt disease-specific therapy. The complexity of the problem is best appreciated by reviewing the differential list, which includes nearly 80 distinct clinical entities. Consequently, a thorough understanding of the more common etiologies is necessary to adequately treat patients with SPNs.

Brain metastases at the time of presentation of non-small cell lung cancer: a multi-centric AERIO analysis of prognostic factors

A multi-centre retrospective study involving 4 French university institutions has been conducted in order to identify routine pre-therapeutic prognostic factors of survival in patients with previously untreated non-small cell lung cancer and brain metastases at the time of presentation. A total of 231 patients were recorded regarding their clinical, radiological and biological characteristics at presentation. The accrual period was January 1991 to December 1998. Prognosis was analysed using both univariate and multivariate (Cox model) statistics. The median survival of the whole population was 28 weeks. Univariate analysis (log-rank), showed that patients affected by one of the following characteristics proved to have a shorter survival in comparison with the opposite status of each variable: male gender, age over 63 years, poor performance status, neurological symptoms, serum neuron-specific enolase (NSE) level higher than 12.5 ng ml(-1), high serum alkaline phosphatase level, high serum LDH level and serum sodium level below 132 mmol l(-1). In the Cox's model, the following variables were independent determinants of a poor outcome: male gender: hazard ratio (95% confidence interval): 2.29 (1.26-4.16), poor performance status: 1.73 (1.15-2.62), age: 1.02 (1.003-1.043), a high serum NSE level: 1.72 (1.11-2.68), neurological symptoms: 1.63 (1.05-2.54), and a low serum sodium level: 2.99 (1.17-7.62). Apart from 4 prognostic factors shared in common with other stage IV NSCLC patients, whatever the metastatic site (namely sex, age, gender, performance status and serum sodium level) this study discloses 2 determinants specifically resulting from brain metastasis: i.e. the presence of neurological symptoms and a high serum NSE level. The latter factor could be in relationship with the extent of normal brain tissue damage caused by the tumour as has been demonstrated after strokes. Additionally, the observation of a high NSE level as a prognostic determinant in NSCLC might reflect tumour heterogeneity and understimated neuroendocrine differentiation.

Cyfra 21-1, neuron specific enolase and prognosis of non-small cell lung cancer: prospective study in 621 patients

BACKGROUND

CYFRA 21-1, a serum cytokeratin 19 fragment, and neuron specific enolase (NSE), the gamma-subunit of enolase, are putative markers of lung cancer. Their clinical applicability as prognostic factors in non-small cell lung cancer (NSCLC) would need an appraisal by simultaneous evaluation of other known survival determinants in a large population followed over a long period.

AIM

To determine the prognostic value of different clinical and routine biological variables at presentation with particular attention paid to the above-mentioned markers.

METHODS

621 histologically proven and previously untreated NSCLC patients have been prospectively studied (seven were lost to follow-up). Median follow-up was 4 years and 2 months. At presentation, 16 clinical and biological variables were recorded. Serum NSE and CYFRA 21-1 were assayed blind without any clinical information given.

RESULTS

The serum CYFRA 21-1 distribution differed significantly according to histology, disease stage and performance status, with the highest levels observed in squamous cell carcinomas, metastatic stage, positive mediastinal nodal status and poor performance status. However, the respective "receiver operating characteristic" curves showed that the CYFRA 21-1 serum level did not accurately predict tumour stage. Serum NSE distribution correlated neither with tumour stage nor with performance index and its sensitivity in the whole NSCLC was low. In the Cox proportional hazard model, the following variables were independent determinants of a poor outcome: performance status 2 or 3, hazard ratio (HR): 2.25; Nodal status N(2-3), HR: 1.84; Metastatic disease, HR: 1.73; NSE>12.5 ng/ml, HR: 1.52; CYFRA 21-1>3.6 ng/ml, HR: 1.41 and Tumour status T(3-4), HR: 1.31. When the survival analysis was restricted to the 274 patients affected by a metastatic stage, we observed that performance status, nodal status, NSE and CYFRA 21-1 remained prognostic determinants with similar hazard ratios.

CONCLUSION

The prognostic information given by a high serum CYFRA 21-1 level is independent from other well-known variables such as performance status and disease stage and is perennial throughout extended follow-up period. A high NSE level also prognosticates a poor outcome probably by reflecting tumour heterogeneity and underestimated neuroendocrine differentiation.

Predictive and prognostic factors in small cell lung cancer: current status

Clinical and laboratory parameters can predict response to chemotherapy and long term survival in small cell lung cancer, and may predict those at risk of early treatment related toxicity. This paper reviews the predictive models that have been developed to divide patients into prognostic groups for response and survival on the basis of clinical and laboratory parameters. These factors may be used for the stratification of patients in clinical trials and to help clinicians make appropriate treatment decisions for individual patients. A number of treatment-related factors can also affect outcomes. The evidence for interventions to prevent treatment deaths in high risk patients, such as prophylactic antibiotics, dosage modification or colony stimulating factor support are also reviewed.

Pathological Examination and the Reporting of Lung Cancer Specimens

The Lung Cancer Disease Site Group (DSG) of the Cancer Care Ontario Practice Guidelines Initiative first met in January of 1994. Included in the membership were three pathologists who, with the other members of the DSG, felt that a useful contribution to the work of the group would be a recommendation on standardized examination and reporting of lung cancer specimens. This review summarizes the consensus of the Lung Cancer DSG pathologists based on their review of the literature and proposes a standard synoptic report, the Primary Lung Cancer Check-Off Sheet. If generally adopted, this standard would improve the quality of reporting of clinical and pathological stage information. Such high-quality staging information is essential to define patient populations for clinical trials and for outcome analyses.

The significance of NSE and CEA as a differentiation marker for the cellular heterogeneity of small cell lung cancer

Neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA) levels in the culture supernatant of the 65 pulmonary carcinoma cell lines: Small cell lung cancer (SCLC) 18, large cell carcinoma 14, squamous cell carcinoma 14, adenocarcinoma 14 and adenosquamous cell carcinoma 5, were measured by a radioimmunoassay (RIA). The mean value of NSE was 30.8+/-22.4 ng/ml and 9.2+/-8.7 ng/ml in SCLC and non-SCLC, respectively. The mean value of CEA was 15.1+/-20.9 ng/ml and 26.6+/-72.3 ng/ml in SCLC and non-SCLC, respectively. A significant difference in NSE levels was obtained between SCLC cell lines and non-SCLC cell lines. In SCLC cell lines, a significant inverse proportional correlation was observed between NSE and CEA levels. The CEA production tended to be higher in cells with low levels of NSE than in those with high NSE production. With respect to correlation between marker production and growth characteristics of SCLC cells in vitro, significantly higher NSE and lower CEA levels were found in cells growing with floating colony or neurite like characteristics (classic cell type) than those in cells with epithelial or intermediate growth characteristics (variant cell type). A significant positive correlation between NSE levels and the survival periods was found in follow-up studies of 10 patients who underwent surgery with complete resection of the primary tumor. All of 4 long term survivors over 3 years after surgery had significantly high NSE and relatively low CEA producing tumors. The relationship of these markers to clinical status of the patient suggests that an analysis for correlation of NSE and CEA levels in SCLC patients may be useful to discriminate between a pure neuroendocrine SCLC tumor and a mixed small cell/large cell tumor, and in monitoring therapeutic effect and prognosis of each patient.

Small cell anaplastic carcinoma of the prostate: seven new cases, review of the literature, and discussion of a therapeutic strategy

Small cell anaplastic carcinoma of the prostate (SCCP) is a rare entity; a literature review disclosed fewer than 150 cases. SCCP has an aggressive course, and both local and distant failure is common. The optimal treatment method has not been clearly established. We review our experience with 7 patients, with attention paid to clinical and pathological details based on a review of the histological specimens. Three patients had mixed tumors of both SCCP and adenocarcinoma, 3 had pure adenocarcinomas that recurred as small cell, and 1 had pure small cell. Our series confirms the aggressive nature of the disease, with all patients dying of their disease < or = 42 months after diagnosis. All patients progressed locally, and at least 5 later developed distant metastases. Treatment with combination chemotherapy and/or hormones resulted in short-lived responses in most patients. We recommend use of hormonal manipulation and combination chemotherapy as well as surgery and/or radiation therapy to the prostate for local control and emphasize that histologic recognition of the entity is important for proper treatment.

Relationship between TA01 and TA02 polypeptides associated with lung adenocarcinoma and histocytological features

TA01 (molecular weight 35.0 kDa, isoelectric point 5.45) and TA02 (molecular weight 35.0 kDa, isoelectric point 5.29) polypeptides were detected using two-dimensional polyacrylamide gel electrophoresis (2-DE). A previous study has shown that these polypeptides are distributed in primary adenocarcinomas and some large-cell carcinomas of the lung. However, various expression levels of TA01 and TA02 polypeptides were demonstrated in adenocarcinoma, while large-cell carcinoma expressed low levels. To evaluate the relationship between the expression of TA01 and TA02 polypeptides and the histocytological features of primary adenocarcinoma of the lung, these two polypeptides were analysed by 2-DE combined with a non-enzymatic sample preparation technique, and their expression levels were compared with the histocytological features of primary lung adenocarcinoma. Out of 57 primary lung adenocarcinoma cases, 46 cases (80.7%) and 52 cases (91.2%) expressed TA01 and TA02 polypeptides respectively. Furthermore, the expression levels of TA01 and TA02 polypeptides correlated with the degree of cellular atypia, structural atypia and histocytological differentiation of primary lung adenocarcinoma. On the other hand, these two polypeptides were not detected in adenocarcinoma of the lung, metastatic from the colon and mammary glands. High expression of TA01 and TA02 polypeptides reflected the differentiation of primary adenocarcinoma in the lung. These two polypeptides are valuable in determining the histocytological differentiation of primary lung adenocarcinoma as well as in distinguishing between primary and metastatic adenocarcinoma of the lung.

Molecular markers help characterize neuroendocrine lung tumors

BACKGROUND

The terms large cell and mixed small-large cell neuroendocrine carcinoma (LCNC, MNC) have been proposed to describe distinct types of high-grade neuroendocrine lung tumors. However, cytologic appearance and neuroendocrine immunohistochemical stains cannot uniformly distinguish these from other neuroendocrine tumors, such as typical and atypical carcinoids or small cell carcinoma, or nonendocrine lung cancers such as large cell undifferentiated carcinoma. This study sought to determine the patterns of expression in LCNC and MNC of several molecular markers often abnormally expressed in lung cancers.

METHODS

Primary lung tumors with neuroendocrine features operated on between 1984 and 1994 were reviewed and classified as typical carcinoid (TC), atypical carcinoid (AC), LCNC, MNC, and small cell lung cancer (SCLC) based on mitotic rate, extent of necrosis, and cytoarchitectural features. Immunohistochemistry was performed using antibodies MIB-1 for Ki67, pAb1801 for p53, OP-66 for Rb, 31G7 for EGFR. Staining was scored as 0 to 4+ (0 = less than 5%, 1+ = 5% to 20%, 2+ = 20% to 50%, 3+ = 50% to 80%, 4+ = more than 80%) for p53, Ki67, and EGFR; and negative, focal, or positive for Rb. Overall survival was calculated by the Kaplan-Meier method and prognostic factors compared by log rank test.

RESULTS

Ninety-two tumors were examined: 25 TC, 7 AC, 24 LCNC, 18 MNC, 18 SCLC. The LCNC and MNC presented more frequently as stage II or III tumors (n = 28, 66%) than TC and AC (n = 5, 15%). Median survival for LCNC and MNC was 18.7 months, for SCLC 14.3 months, and has not been reached for TC and AC tumors. TC and AC tumors were uniformly characterized by low proliferative rate, absent p53, and normal Rb staining. LCNC, MNC, and SCLC showed a high proliferative rate, abnormal p53, and absent Rb staining. Overexpression of EGFR was frequent in all five tumor types.

CONCLUSIONS

(1) Ki67, p53, and Rb help distinguish LCNC and MNC from TC and AC. (2) Small numbers of patients preclude comparison of survival rates, but LCNC/MNC have a median survival similar to comparable early stage SCLC, and clearly worse than TC/AC. These results justify a sharp separation of high-grade neuroendocrine tumors from carcinoids, and suggest a close relationship between LCNC, MNC, and SCLC.

Histologic changes in small cell lung carcinoma after treatment

BACKGROUND

Small cell lung carcinoma (SCLC) has been divided into three subtypes: pure SCLC, mixed small cell/large cell carcinoma (mixed SC/LC), and combined SCLC. Patients with mixed SC/LC show a worse prognosis than those with pure SCLC.

METHODS

Persistence of histologic subtype in SCLC in the primary sites during the course of treatment or in the different organs at autopsy was examined. For this purpose, biopsy or cytologic specimens before chemotherapy, and autopsy specimens from 175 patients with SCLC were reviewed. They included 147 (84%) men and 28 (16%) women with an age range of 29-83 (median, 65) years.

RESULTS

The frequency of mixed SC/LC in the primary sites was statistically higher in autopsy (14.3%) than that in biopsy or cytology specimens (8.6%) (P < 0.05). At autopsy, involved organs were categorized into two groups according to frequency of appearance of mixed SC/LC, i.e., a higher frequency group, including the liver (31 of 85; 36.4%), adrenal gland (15 of 56; 26.8%), brain (6 of 9; 66.7%), and extrathoracic lymph nodes (17 of 59; 28.8%) and a lower frequency group, including the lung (metastatic sites) (12 of 102; 11.8%), pleura (8 of 74; 10.8%), and intrathoracic lymph nodes (12 of 94; 12.8%). The difference in frequency between these two groups was statistically significant (P < 0.05).

CONCLUSIONS

These findings suggest that primary pure SCLC can progress to mixed SC/LC with an increased potential for distant metastasis.

NCI series of cell lines: an historical perspective

The NCI series of cell lines represent a unique collection of permanent human tumor cell lines established by one laboratory over a period of approximately 16 years. More than 300 cell lines were established, mainly from human lung cancers (both small cell and non-small cell types). In addition, smaller numbers of lines were established from rare and unusual tumors such as cutaneous T cell lymphomas, myelomas and adrenal cortical carcinoma. The T cell lines played a pivotal role in the isolation of human retroviruses including HTLV-1 and HIV. The establishment of such a large panel of lines was aided by the development of defined media for culturing specific cell types. The lines are well characterized, and full clinical data are available for most of them. Many of the lines have been deposited with the American Type Culture Collection, Rockville, MD, where they are readily available for a modest handling fee. The lines have been widely distributed to investigators, and have had a major impact on biomedical research.

Detection of polypeptides associated with the histopathological differentiation of primary lung carcinoma

Two-dimensional polyacrylamide gel electrophoresis combined with a non-enzymatic sample preparation technique is useful for analysing clinical tumour material. Using these techniques, we analysed the relationship between the histopathological findings in primary lung malignancies and the expression of a number of unidentified polypeptides that were detected in the molecular weight region 20-35 kDa. In this study 45 cases of primary lung cancer (PLC) (21 cases of adenocarcinoma, ten cases of squamous cell carcinoma, five cases of large-cell carcinoma, one case of adenosquamous cell carcinoma, five cases of small-cell carcinoma and three cases of carcinoid tumour) were examined. For reference, a human diploid fibroblast cell line (W138) and normal peripheral lymphocytes were used. Sixteen polypeptides were judged to be associated with histopathological features. These polypeptides seem to be valuable as differentiation markers. The simultaneous evaluation of these polypeptides and some other proliferation markers (e.g. PCNA, PCNA 'satellite', Numatin/protein B23 and lamin B) seems to clarify the characteristics of each case of PLC. Furthermore, it is possible to classify PLC based on the two-dimensional electrophoresis findings, and this classification of PLC is suggested to reflect the biological features of the tumour more precisely than that based only on morphology.

Increased radioresistance of an in vitro transformed human small cell lung cancer cell line

After 4-6 months in continuous culture the human small cell lung cancer (SCLC) cell line, U-1906, changed its radiobiological characteristics spontaneously. The cell line became more radioresistant indicating an increased repair capacity. This change was accompanied by a more adherent growth pattern, a higher clonogeneity, a decrease in the cytokeratin (tissue polypeptide antigen) content and increased glucagon and neuron-specific enolase (NSE) production. Other parameters such as the estramustine-binding protein (EMBP) and the proliferation associated antigen Ki-67 were unaltered. This spontaneous transformation in vitro of U-1906 may reflect a clinically important in vivo phenomenon of SCLC, which frequently develops resistance both to radio- and chemotherapy.

Alternative splicing of the neurofibromatosis 1 gene correlates with growth patterns and neuroendocrine properties of human small-cell lung-carcinoma cells

Two distinct transcripts, type I and type II, of the neurofibromatosis I (NFI) gene are generated by alternative splicing in the region corresponding to the gene's GTPase-activating protein-related domain (GRD). Relative expression levels of these 2 transcripts were previously correlated to neural differentiation. Since small-cell lung carcinoma (SCLC) often exhibits neuroendocrine properties, we analyzed the type-I to type-II mRNA ratio in 15 SCLC cell lines, using reverse transcriptase and polymerase chain reaction methods. The type-I mRNA was predominant in 10 cell lines; 8 of them grew as floating aggregates in culture and had high L-dopa decarboxylase (DDC) activity. The other 5 lines predominantly expressed type-II mRNA, adhered to the culture substrate, and expressed low or undetectable levels of neural cell-adhesion molecule (NCAM) antigen and DDC activity. N2+, one of the subclones of NCI-N417 cells, exhibited a higher type-I to type-II ratio after the cells had adhered to a laminin-coated plate and had emitted neurite-like processes. These findings provide evidence that alternative splicing patterns of NFI mRNA correlate with the mechanisms that regulate the growth patterns and neuroendocrine properties of SCLC cells in vitro.

Evolution of chromosomal alterations and biologic features in two small cell lung carcinoma cell lines established from one patient during the course of the disease

Two small cell lung cancer (SCLC) cell lines were established from metastases of a patient during the course of the disease. SCLC 74A was derived from biopsy material obtained at the time of diagnosis and SCLC 74B was from a biopsy specimen of a relapsed tumor obtained after treatment. A transition occurred from SCLC 74A, an intermediate form with 5% large cells to SCLC 74B, a standard mixed form with 20% of large cells, with a decrease in neuroendocrine markers and a substantial increase in P-glycoprotein, a multidrug resistance marker. For both cell lines, R-banding and FISH indicated a del(1)(p35pter) also found in other neural-crest-derived tumors, the loss of regions with suspected tumor suppressor genes at 3p, 5q, and 17p, and a recurrent translocation of the 6q24-6qter region to 10p14. Further genetic modifications in SCLC 74B affected chromosomes 2, 3, 5, 10, 11, 14, and 15. The main observations were a der(2)t(2;5)(p16;q?); a der(3;11)(q10;p10) in SCLC 74A which became der(3;14)(q10;p10) and der(11;14)(p10;q10) in SCLC 74B; and the insertion of the 5q13-5q31 region in the der(10)t(6;10). The finding of the same structural abnormalities in both cell lines suggests a monoclonal origin for both metastases. Hypotetraploid cells were in the same proportion as large cells whose number was a characteristic feature of each cell line. They possessed twice the same chromosomal alterations observed in the hypodiploid cells. This suggests a permanent process of tetraploidization.