Faculty Bibliography

PURPOSE: Recent evidence suggests that at least some sarcomas arise through aberrant differentiation of mesenchymal stromal cells (MSCs), but MSCs have never been isolated directly from human sarcoma specimens. EXPERIMENTAL DESIGN: We examined human sarcoma cell lines and primary adherent cultures derived from human sarcoma surgical samples for features of MSCs. We further characterized primary cultures as either benign or malignant by the presence of tumor-defining genetic lesions and tumor formation in immunocompromised mice. RESULTS: We show that a dedifferentiated liposarcoma cell line DDLS8817 posesses fat, bone, and cartilage trilineage differentiation potential characteristic of MSCs. Primary sarcoma cultures have the morphology, surface immunophenotype, and differentiation potential characteristic of MSCs. Surprisingly, many of these cultures are benign, as they do not form tumors in mice and lack sarcoma-defining genetic lesions. Consistent with the recently proposed pericyte origin of MSCs in normal human tissues, sarcoma-derived benign MSCs (SDBMSCs) express markers of pericytes and cooperate with endothelial cells in tube formation assays. In human sarcoma specimens, a subset of CD146-positive microvascular pericytes expresses CD105, an MSC marker, whereas malignant cells largely do not. In an in vitro coculture model, SDBMSCs as well as normal human pericytes markedly stimulate the growth of sarcoma cell lines. CONCLUSIONS: SDBMSCs/pericytes represent a previously undescribed stromal cell type in sarcoma that may contribute to tumor formation.

INTRODUCTION: Primary lung adenocarcinoma is extremely rare in the pediatric age group. There have been anecdotal reports of lesions that are histologically indistinguishable from adult-type pulmonary adenocarcinoma in young patients after treatment for nonpulmonary cancers. Herein, we present clinical, histopathologic, and molecular data on eight such cases. METHODS: Histopathologic evaluation of the tumors was performed according to the World Health Organization classification. Molecular studies for EGFR and KRAS mutations were performed on six patients with sufficient material. RESULTS: All eight patients were never smokers, four males and four females. Median age at nonpulmonary cancer diagnosis was 14 years (range, 3-23 years). Pulmonary adenocarcinomas were diagnosed at a median age of 15 years (range, 10-24 years); tumors were 0.1 to 2.0 cm in size and in some cases coexisted with metastases from the original cancer. Retrospective review showed that in at least three patients, the nodules were radiographically present before chemotherapy. Of six patients whose tumors were tested for common EGFR and KRAS mutations, two were positive for the former and one for the latter. At a median follow-up of 11 months (range, 2-29 months), six patients remained well without lung nodules and two had additional small, peripheral lung nodules that have not been biopsied. CONCLUSIONS: Pulmonary lesions found in young patients with pediatric cancers can be histologically indistinguishable from lung adenocarcinoma seen in adults, may display typical adenocarcinoma-associated mutations of EGFR and KRAS, and may precede the administration of cytotoxic chemotherapy.

Currently no objective grading system for pulmonary adenocarcinomas exists. To determine whether specific histologic patterns or combinations thereof could be linked to an objective grading system, the histologic patterns in metastatic tumor deposits was compared with the patterns seen in the corresponding 73 primary tumor to determine whether a specific pattern had higher propensity to metastasize. The concordance of the predominant histologic pattern in the primary tumor and the metastases was of 100% for micropapillary, 86% for solid, 42% for acinar, and 23% for papillary types of adenocarcinoma. Informed by these results, a 3-tier grading system based on the histologic subtypes was established. Grade I, a pattern with low metastatic potential (BAC); Grade II, patterns with intermediate metastatic potential (acinar and papillary); and Grade III, patterns with high metastatic potential (solid and micropapillary). These grades were combined into a number of different scoring systems, whose ability to predict recurrence or death from disease was tested in 366 stage 1 adenocarcinomas. A score based on the 2 most predominant grades was able to stratify patients into low-to-high risk for recurrence or death of disease (P=0.001). The 5-years disease-free survival for patients in the highest score group was of 0.73, compared with 0.84 and 0.92 in the intermediate and lowest score groups. Concordance probability estimate was 0.65 (95% confidence interval 0.57-0.73). Therefore, this scoring system provides valuable information in discriminating patients with different risk of disease-recurrence in a highly homogeneous population of patients with stage I cancer.

Carcinomas may arise as a disorder of regeneration, so that a malignant cell may represent a failure to fully attain the characteristics of differentiated tissue. We hypothesized that there is a differential distribution of progenitor cell markers among different histological types of lung cancers, with poorly differentiated tumors being more likely to express progenitor stem cell markers. The study was limited to paraffin-embedded archival material of resected untreated pulmonary carcinomas, including adenocarcinoma, squamous cell carcinoma, large cell carcinoma, and small cell carcinoma. The sections were stained for putative stem cells markers (Musashi-1, Musashi-2, CD34, CD21, KIT, CD133, p63, and OCT-4). Positivity was read as isolated, focal, or diffuse staining. Stem cell markers were detected in all histological types of pulmonary carcinomas. There was a difference in the expression of markers among the histological types. Small cell carcinoma showed diffuse positivity for most of the markers; in contrast to focal or negative staining in other histological groups. An inverse relationship between CD21 and Musashi-1 was observed. No staining for OCT-4 and CD34 was seen in any of the tumor types. Hierarchical clustering based on marker expression separated tumors into two groups, with one group marked by high expression of Musashi-1 and KIT, contained most of the poorly differentiated adenocarcinomas and small cell carcinomas. Therefore, stem cell markers are expressed in lung cancers with different patterns seen for different histological types and degrees of differentiation.

Short and long-term pulmonary response to inhaled nickel hydroxide nanoparticles (nano-Ni(OH)(2), CMD = 40 nm) in C57BL/6 mice was assessed using a whole body exposure system. For short-term studies mice were exposed for 4 h to nominal concentrations of 100, 500, and 1000 mg/m(3). For long-term studies mice were exposed for 5 h/d, 5 d/w, for up to 5 months (m) to a nominal concentration of 100 mg/m(3). Particle morphology, size distribution, chemical composition, solubility, and intrinsic oxidative capacity were determined. Markers of lung injury and inflammation in bronchoalveolar lavage fluid (BALF); histopathology; and lung tissue elemental nickel content and mRNA changes in macrophage inflammatory protein-2 (Mip-2), chemokine ligand 2 (Ccl2), interleukin 1-alpha (Il-1alpha), and tumor necrosis factor-alpha (Tnf-alpha) were assessed. Dose-related changes in BALF analyses were observed 24 h after short-term studies while significant changes were noted after 3 m and/or 5 m of exposure (24 h). Nickel content was detected in lung tissue, Ccl2 was most pronouncedly expressed, and histological changes were noted after 5 m of exposure. Collectively, data illustrates nano-Ni(OH)(2) can induce inflammatory responses in C57BL/6 mice

The most recent WHO classification of lung cancer defines bronchioloalveolar carcinoma (BAC) as a noninvasive carcinoma or adenocarcinoma in situ. However, the use of this terminology is not uniform and does not reflect standardized criteria. As a result, the diagnosis of BAC has been used in association with small, solitary, and well-differentiated adenocarcinoma as well as tumors with advanced clinical stage. At present, there is a growing consensus among specialists in thoracic oncology that BAC or adenocarcinoma in situ is a rare tumor, and the term should be restricted to adenocarcinomas that show a pure lepidic pattern of growth. The amount of invasive component present in a tumor with a predominant lepidic growth pattern has also been under intense scrutiny. The concept of minimally invasive adenocarcinoma is developing in order to differentiate a pure BAC from an invasive adenocarcinoma that still carries an excellent prognosis.

Our objective was to describe the clinicopathologic features of epithelioid trophoblastic tumors (ETTs) in a series of patients who presented with elevated beta-human chorionic gonadotrophin (hCG) levels and extrauterine lesions resembling primary lung carcinomas. Clinical and pathologic materials were reviewed and Shih and Kurman's diagnostic criteria were applied. Three parous women (38, 49, and 34 y of age) with elevated beta-hCG levels had nondiagnostic gynecologic evaluations, including negative dilation and curettage specimens. Imaging revealed isolated pulmonary lesions, 2 to 8.5 cm in size, resembling primary lung carcinomas. Two patients received multiagent chemotherapy consisting of etoposide, methotrexate, dactinomycin, alternating with cisplatin and etoposide, and all underwent pulmonary resection. Histologically, the cytologic features, epithelioid growth pattern, and hyaline-like material simulated the appearance of nonsmall cell lung carcinoma, but overall, the histologic features along with the immunophenotype supported classification as ETT. Follow-up hysterectomy specimens were histologically normal. All 3 patients are alive and well. The rarity of ETT and its resemblance to squamous and pleomorphic carcinomas of lung have led to diagnostic difficulties. When reproductive-age women present with elevated beta-hCG levels, a pulmonary lesion, and no apparent intrauterine disease, primary pulmonary ETT should be considered. Correlating clinical indices with specific morphologic and immunohistochemical features can ensure diagnostic accuracy and appropriate treatment for favorable outcomes.

Micropapillary adenocarcinoma is associated with poor-prognosis in several organs including the lung. The presence of small tight balls of neoplastic cells devoid of fibrovascular core in cytological preparations (micropapillary tufts) has been described as characteristic of micropapillary adenocarcinoma. In the lung, however, this criterion has not been validated. The cytological material of 46 cases of histologically proven pulmonary adenocarcinoma with a micropapillary component was compared to 33 cases with no micropapillary component to determine the specificity of micropapillary tufts for the histologic diagnosis of micropapillary adenocarcinoma. Other histologic patterns of invasive pulmonary adenocarcinomas (acinar, papillary, and solid) were also compared with patterns of neoplastic cell aggregates in cytological preparations. There were no significant differences in the distribution of micropapillary clusters between the two groups. The positive predictive value for the cytologic diagnosis of a micropapillary component in lung adenocarcinomas was of 64%. Similar findings were observed for other invasive patterns. Therefore, the detection of micropapillary tufts in cytology is not specific for the diagnosis of a pulmonary micropapillary adenocarcinoma in the lung.