Melanoma antigen expression in serial fine-needle aspiration samples in patients with metastatic malignant melanoma participating in immunotherapy clinical trials: a preliminary look.

BACKGROUND: MART-1 and gp100 currently are utilized as targets in immunotherapy protocols for metastatic malignant melanoma (MMM). Enrollment of patients into ongoing peptide vaccination trials at the National Cancer Institute includes immunophenotyping of samples of metastatic lesions obtained by fine-needle aspiration (FNA). As therapy progresses, immunocytochemistry is performed on serial FNAs of metastatic lesions to monitor changes in antigen expression during treatment. It is theorized that antigen expression of melanoma cells may be diminished because of selective immunodestruction of tumor cells, or perhaps intentionally, to escape immunosurveillance. METHODS: Thirty-eight lesions from 33 patients were serially monitored for the expression of gp100 (clone HMB-45) and MART-1 (clone M2-7C10), using an avidin-biotin peroxidase technique. The staining intensity of tumor cells was scored on a scale of 0 to 3+, with the proportion of positive cells categorized as less than 25%, 25-50%, 50-75%, and greater than 75%. All lesions were examined within approximately 2 months after the start of peptide vaccination, providing a consistent timepoint for analysis. RESULTS: Using the Wilcoxon signed rank test, the authors found that there were no significant changes from baseline compared with 2 months later for quantitative antigen expression of HMB-45 or MART-1. However, there was a trend toward a decline in staining intensity of tumor cells for HMB-45. CONCLUSIONS: Preliminary results evaluating antigen expression during selective immunotherapy indicate a trend in the decline of staining intensity of tumor cells to HMB-45. Thus, although other studies have shown that peptide-based immunotherapy results in immune selection, this does not hinder the diagnostic utility of antibodies to HMB-45 and MART-1 in FNA samples of MMM.

Absence of SV-40 large T antigen (Tag) in malignant mesothelioma effusions: an immunocytochemical study.

Simian Virus 40 (SV 40) was recently implicated in the pathogenesis of malignant mesothelioma. The oncogenic capacity of SV-40 is a function of a nuclear protein, the large T antigen (Tag). SV-40 Tag DNA sequences are detected by the polymerase chain reaction in 40-80% of malignant mesothelial proliferations. However, the role of immunohistochemistry (IHC) in demonstrating the nuclear localization of Tag is controversial. We sought to determine the clinical utility of SV-40 Tag IHC in pleural effusion cytology as an ancillary tool in the cytologic diagnosis of malignant mesothelioma (MM). Formalin-fixed, paraffin-embedded cell block sections from 100 pleural effusions (32 MMs, 25 benign reactive, 43 metastatic adenocarcinomas) were immunostained for the SV-40 anti-Tag, using two primary monoclonal SV-40 Tag antibodies: clone Pab 416 and clone Pab 101. Despite strong and consistent immunoreactivity in positive controls, no nuclear immunostaining was observed in any case. We believe the small sample size in cytology cell block sections, the low viral copy number in infected cells, and the effect of formalin fixation may have resulted in absence of immunoreactivity. The role of SV-40 Tag IHC in diagnostic cytopathology remains unclear unless further studies reliably show its detection.

Immunocytochemistry in effusion cytology: a contemporary review.

BACKGROUND: Cytology plays a pivotal role in the diagnosis of pleural effusions. In many cases, immunocytochemistry (ICC) is required to elucidate the etiology of the atypical cells. Effusions are samples that present unique problems for ICC. To date there is no standardization of ICC methods for effusions and cytology in general. METHODS: The authors review the most commonly used cytologic preparations, fixatives, and antibodies used in effusion ICC. RESULTS: Through the utilization of cell block preparations and a panel of antibodies appropriate for the differential diagnosis in question, ICC conditions utilized in surgical pathology can be most closely replicated. CONCLUSIONS: ICC may provide reliable insights into various diagnostic dilemmas in effusion cytology, provided that laboratory standardization practices are followed.

Comparison of antibodies to HBME-1 and calretinin for the detection of mesothelial cells in effusion cytology.

The distinction of mesothelial cells in cytologic samples is often a diagnostic challenge. This is particularly true in potentially malignant effusions in which reactive mesothelial cells may simulate adenocarcinoma (ACA) cells, and in the differentiation of ACA vs. mesothelioma. We sought to determine the superior antibody for the positive identification of mesothelial cells in these circumstances. Cell block sections of 25 reactive and 8 malignant mesothelioma effusions were immunostained with an avidin-biotin procedure, using antibodies to HBME-1 and calretinin. No pretreatment of samples was necessary for the HBME-1-stained slides; microwave antigen retrieval was performed on all slides stained for calretinin. A negative control was performed on each sample. The staining intensity of tumor cells was scored on a scale of 0-3+, with the proportion of immunoreactive cells categorized as <25%, 25-50%, 50-75%, and >75%. The predominant staining pattern for HBME-1 was surface, with rare samples also exhibiting cytoplasmic staining as well. The calretinin-staining pattern was cytoplasmic, with peripheral condensation/prominence and accompanying nuclear staining. All samples were immunoreactive with both antibodies. Fifty-five percent (18/33) of samples showed significantly stronger immunoreactivity with calretinin than with HBME-1; 45% (15/33) of samples showed equivalent staining with the two markers. None of the samples in this study showed stronger immunoreactivity with HBME-1 than with calretinin. Sixty-one percent (20/33) of samples stained with HBME-1 at a moderate (2+) intensity. Fifty-five percent (18/33) of samples stained with calretinin at a strong (3+) intensity. While only 12% of samples showed >75% immunoreactivity for HBME-1, 58% of samples showed >75% of cells immunoreactive for calretinin. Calretinin is the preferred marker in identifying mesothelial cells in cytologic samples, showing the highest sensitivity for mesothelial cells, as evidenced by a more intense staining reaction in a higher percentage of cells than with HBME-1. Published 2001 Wiley-Liss, Inc.

Short-term kinetics of tumor antigen expression in response to vaccination.

The melanoma patient's immune response to tumor has been extensively studied. Yet, the frequently observed coexistence of tumor-associated Ag (TAA)-specific T cells with their target cells in vivo remains unexplained. Loss of TAA expression might contribute to this paradox. We studied TAA expression in metastases by obtaining fine-needle aspirations from 52 tumor lesions in 30 patients with melanoma before and soon after immunotherapy. Limitations due to low amounts of starting material were overcome with a high fidelity antisense RNA amplification method. TAA expression was measured by quantitative real-time PCR of anti-sense RNA. Decrease in gp100/Pmel-17 TAA preceded tumor disappearance in several instances and could be best explained by immune selection because most patients had received gp100/Pmel-17-specific vaccination. Conversely, immune selection was absent in nonregressing lesions. These observations suggest that vaccination, when successful, triggers a broad inflammatory reaction that can lead to tumor destruction despite immune selection. Additionally, lack of clinical response might be attributed to lack of this initiating event rather than immune escape. This study provides an insight into the natural history of tumors and defines a strategy for the characterization of gene expression in tumors during therapy.

Detection of loss of heterozygosity at chromosome 3p25-26 in primary and metastatic ovarian clear-cell carcinoma: utilization of microdissection and polymerase chain reaction in archival tissues.

Loss of heterozygosity (LOH) at the 3p region is found in up to 50% of epithelial ovarian neoplasms. The von Hippel-Lindau (VHL) gene at the 3p25 locus is one of the tumor-suppressor genes located at 3p. The role, if any, of the VHL gene locus is not clear in ovarian carcinogenesis. We analyzed primary and metastatic ovarian clear-cell carcinomas (OCCC) for LOH at 3p25 to determine its frequency and its diagnostic utility as an adjunctive tool in the differential diagnosis of metastatic clear-cell carcinomas. Microdissection followed by single-step DNA extraction and polymerase chain reaction (PCR) amplification, using two polymorphic markers flanking the VHL gene locus, was done on archival histology and cytology samples from 9 patients with metastatic OCCC. Of the informative cases, 43% of the metastatic and 50% of the primary OCCC showed LOH. LOH at the VHL gene locus is not uncommon in clear-cell ovarian carcinoma. LOH at 3p25 in cytologic specimens may be a valuable adjunct in the diagnosis of OCCC metastasis in cytologically equivocal cases. OCCC should enter the differential in clear-cell carcinomas of unknown primary that show LOH at 3p25. Published 2001 Wiley-Liss, Inc.

Laser scanning cytometry evaluation of MART-1, gp100, and HLA-A2 expression in melanoma metastases.

Assessment of antigen expression by solid tumors has relied predominantly on immunohistochemistry, flow cytometry, and more recently quantitative real-time polymerase chain reaction. However, all these techniques present intrinsic limits. The laser scanning cytometer, by combining the properties of light and fluorescence microscopy with those of laser cytometry, can quantitatively and objectively analyze hypocellular samples such as fine-needle aspirates on an individual cell basis. To validate the fidelity of laser scanning cytometry for quantitative immunophenotyping of fine-needle aspirates, the authors measured the expression of the melanoma-associated antigens MART-1 and gp100 as well as HLA-A2, a HLA class 1 restriction element associated with their recognition by melanoma-specific T cells. Expression of melanoma antigens and HLA was measured by laser scanning cytometry and immunohistochemistry in fine-needle aspirates from melanoma metastases. In addition, transcription levels of both melanoma antigens were recorded by quantitative real-time polymerase chain reaction. A quantity of less than 1,000 cells per sample (average 682 cells) was sufficient for the analysis. Laser scanning cytometry estimates correlated with those of immunohistochemistry and quantitative real-time polymerase chain reaction for MART-1 and gp100. A good correlation in HLA-A2 detection by laser scanning cytometry and immunohistochemistry was also observed. Moreover, the laser scanning cytometer could discriminate subsets of cells from the same lesion with heterogeneous melanoma antigen expression, leading to the observation that cells with a DNA index greater than 2.5 expressed significantly less gp100. Thus, laser scanning cytometry yields detailed information on protein expression in individual cells and represents a new tool for dissecting the immune response in the tumor microenvironment.

Tyrosinase immunoreactivity in fine-needle aspiration samples of metastatic malignant melanoma.

BACKGROUND: Tyrosinase, the rate-limiting enzyme in melanin synthesis, is a melanoma associated antigen that is recognized by both CD4+ and CD8+ T-cells in an HLA-restricted fashion. Peptides derived from the tyrosinase antigen currently are being utilized as a target for T-cells in several immunotherapy protocols for metastatic malignant melanoma (MMM) at the National Institutes of Health/National Cancer Institute. Serial fine-needle aspirations of metastatic lesions are performed to monitor the antigen expression of tyrosinase during treatment by immunostaining cytologic preparations with the monoclonal antibody T311. METHODS: In the current study, 62 samples of MMM were evaluated for tyrosinase immunoreactivity on air-dried, acetone fixed cytospins and the corresponding formalin fixed, paraffin embedded cell block using an avidin-biotin immunoperoxidase method. RESULTS: Positive immunoreactivity revealed a granular cytoplasmic staining in melanocytic cells. The current study results showed that 92% of samples (57 of 62) were T311 immunoreactive on cell block preparations, whereas only 61% (38 of 62) were immunoreactive on cytospin preparations. In 66% of samples (41 of 62) immunoreactivity for T311 was greater in the cell block sample than in the corresponding cytospin, whereas in only 3% of samples (2 of 62) was it greater in the cytospins. In 31% of samples (19 of 62) there was no significant difference in immunoreactivity between the 2 sample types. CONCLUSIONS: The results of the current study show that tyrosinase is a sensitive marker for the detection of MMM; however, the optimal method of sample preparation for immunoperoxidase staining appears to be formalin fixation and paraffin embedding as tyrosinase immunoreactivity is diminished significantly in air-dried cytospin samples despite subsequent acetone fixation. Cancer (Cancer Cytopathol)

Detection of circulating tumor cells and micrometastases in stage II, III, and IV breast cancer patients utilizing cytology and immunocytochemistry.

Evaluation for circulating tumor cells and bone marrow micrometastases has generated considerable interest due to a potential association with disease recurrence and poor prognosis. In this study, we examined bone marrow and apheresis samples from Stage II, III, and IV patients (n 120) enrolled in various clinical breast cancer trials at the National Institutes of Health/National Cancer Institute. For each patient sample, two Diff-Quik-stained cytospins were reviewed for morphology, and approximately 1 x 10(6) cells were analyzed for the expression of cytokeratins using an avidin-biotin immunoperoxidase method. Keratin-positive malignant cells appearing as single cells or in small clusters were detected in bone marrow samples from Stage IV patients only (9/68, 13%) and detected in apheresis samples from both Stage III and IV patients (13/245, 5%). These findings indicate that the combination of cytomorphology with immunocytochemistry can be utilized for the investigation of circulating tumor cells and bone marrow micrometastases, and that positive results appear to correlate with high tumor stage/burden.

The multidrug-resistant phenotype associated with overexpression of the new ABC half-transporter, MXR (ABCG2).

Mechanisms of drug resistance other than P-glycoprotein are of increasing interest as the list of newly identified members of the ABC transport family has grown. We sought to characterize the phenotype of the newly discovered ABC transporter encoded by the mitoxantrone resistance gene, MXR, also known as ABCP1 or BCRP. The pharmacodynamics of mitoxantrone and 12 other fluorescent drugs were evaluated by confocal microscopy in four multidrug-resistant human colon (S1) and breast (MCF-7) cancer cell lines. We utilized two sublines, MCF-7 AdVp3000 and S1-M1-80, and detected overexpression of MXR by PCR, immunoblot assay and immunohistochemistry. These MXR overexpressing sublines were compared to cell lines with P-glycoprotein- and MRP-mediated resistance. High levels of cross-resistance were observed for mitoxantrone, the anthracyclines, bisantrene and topotecan. Reduced levels of mitoxantrone, daunorubicin, bisantrene, topotecan, rhodamine 123 and prazosin were observed in the two sublines with high MXR expression. Neither the P-glycoprotein substrates vinblastine, paclitaxel, verapamil and calcein-AM, nor the MRP substrate calcein, were extruded from MCF-7 AdVp3000 and S1-M1-80 cells. Thus, the multidrug-resistant phenotype due to MXR expression is overlapping with, but distinct from, that due to P-glycoprotein. Further, cells that overexpress the MXR protein seem to be more resistant to mitoxantrone and topotecan than cells with P-glycoprotein-mediated multidrug resistance. Our studies suggest that the ABC half-transporter, MXR, is a potent, new mechanism for conferring multiple drug resistance. Definition of its mechanism of transport and its role in clinical oncology is required.

Individual specimen triage of effusion samples: an improvement in the standard of practice, or a waste of resources?

The standard of practice in cytopathology does not include an individual specimen triage (IST) for sample optimization, but rather prescribes a uniform procedure, e.g., for smears, cell blocks, and cytospins. IST requires additional resources. We sought to evaluate whether IST would result in enhanced diagnostic accuracy and specimen turnaround time in effusions. In order to evaluate the efficacy of IST, 50 effusion samples (31 pleural, 16 peritoneal, and 3 pericardial), each with a minimum volume of 50 ml, were utilized. Each sample was prepared via IST to include at least two initial prepared Diff-Quik-stained cytospins on which the IST was based, as well as a standard cytopreparation protocol for nontriaged samples (NTS) which was limited to 3 smears (2 Papanicolaou-stained, and 1 Diff-Quik-stained) and a hematoxylin-eosin (H&E)-stained cell block section. All triaged and NTS were reviewed retrospectively to determine if IST offered any advantages over the standard cytopreparation protocol for effusion samples. Each was evaluated for diagnostic concordance, turnaround time for final diagnosis, and optimal preparation. In 46 cases, diagnoses in IST and NTS were 100% concordant. Four cases showed minor discrepancies between the original and the NTS diagnoses. In general, the discordant cases were due to sparse cellularity in a specimen composed largely of blood. There was no difference in turnaround time for final diagnosis. Based on a review of all samples, the combination of cell block preparation and cytospins (stained with Diff-Quik and Papanicolaou stains) were considered optimal for microscopic evaluation. IST offers no practical advantage over the NTS standard specimen preparation in relation to the accuracy of final diagnosis or turnaround time. The lysing of grossly bloody fluids with subsequent preparation of cytospins yielded superior preparations for microscopic evaluation over NTS. The standard preparation of effusion samples should include the preparation of a cell block, and cytospins stained with Diff-Quik and Papanicolaou stains, for optimal microscopic evaluation.

Development and characterization of melanoma cell lines established by fine-needle aspiration biopsy: advances in the monitoring of patients with metastatic melanoma.

The establishment of melanoma cell lines from fine-needle aspiration biopsies (FNAB) has allowed for an enhanced understanding of the complex interactions that occur between T cells and tumor cells. The technique of FNAB offers the advantage of providing a sequential analysis of the same tumor nodules throughout treatment. The expression of melanoma antigens (MAs) was assessed in fresh melanoma FNAB samples and from tumor cell lines derived from these samples using several different approaches. Cytospin preparations of freshly isolated tumor cell explants were analyzed by immunocytochemistry (ICC), while the daughter cell line was analyzed by fluorescent activated cell sorting (FACS) analysis, and semiquantitative and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR, qRT-PCR). As assessed by these methods, the level of MA expression by the original tumor cell explants correlated with the expression in established in vitro cell lines. Molecular analysis of the established cell lines utilizing PCR technology improved the sensitivity of detection of MA expression. Thus FNAB of melanoma is an efficient and effective method of tissue procurement, capable of generating, sequentially and from the same lesion, fresh tumor cells, tumor infiltrating lymphocytes (TIL), and long-term melanoma cell lines.

Costimulatory markers in muscle of patients with idiopathic inflammatory myopathies and in cultured muscle cells.

In an attempt to understand the mechanisms of cell injury in the inflammatory myopathies, we analyzed the expression of costimulatory molecules, CTLA4, CD28, CD86, CD40, and CD154 as well as HLA class I, HLA class II, and ICAM-I in normal muscle and in muscle biopsies from patients with polymyositis (PM) or dermatomyositis (DM). By immunohistochemical staining, DM and PM biopsies showed the presence of CTLA4, CD28, CD86, and CD40 on inflammatory cells. More strikingly, however, low levels of CTLA4 and CD28 were observed on muscle cells. The expression of CTLA4 and CD28 on nonlymphoid cells has not been previously reported. These unexpected findings were confirmed in cultured normal human myoblasts: various proinflammatory cytokines induced the expression of CTLA4 and CD28 on normal human muscle cells. The sequences of the cDNAs were found to be identical to the sequences for these molecules in T cells. The data suggest a novel complexity in the network of cellular interactions between the infiltrated immune cells and the muscle cells in which the normal relationship between infiltrating inflammatory cells and target tissue is under a previously unrecognized set of controls.

Utilization of microdissection and the polymerase chain reaction for the diagnosis of adrenal cortical carcinoma in fine-needle aspiration cytology.

BACKGROUND: Loss of heterozygosity (LOH) for several tumor suppressor genes (including loci on 3p, 1p, and 17p,) has been documented in surgical specimens of adrenal cortical carcinomas (ACCA) without accompanying losses in benign hyperplastic and adenomatous adrenal cortical lesions (ACL). This disparate pattern of LOH raises the possibility of exploitation of these differences for diagnostic utilization. Cytologic differentiation of benign versus malignant ACL may be impossible based solely on fine-needle aspiration (FNA) material. The authors attempted to extrapolate the genetic findings on surgical specimens to FNA specimens of ACL to determine whether LOH studies could be utilized as a definitive diagnostic tool. METHODS: Microdissection of archival material was performed on FNAs of ten ACCAs (stained with the Papanicolaou and Diff-Quik stains) with corresponding histologic material (stained with hematoxylin and eosin), one FNA of a benign ACL, and three touch preparations of benign adrenal cortex. LOH analysis was performed by polymerase chain reaction (PCR) with flanking markers for the following putative tumor suppressor genes: p53 (17p13; TP53), 1p (1p36; D1S165), and the von Hippel-Lindau gene at 3p25 (D3S1038 and D3S1110). RESULTS: Similar results were obtained with cytologic and histologic material. As expected, benign ACL showed no LOH for the markers examined. Of the informative ACCA cases, 70% showed LOH for at least 1 of the 3 markers tested on both FNA and histologic samples. For all cases with amplifiable DNA, there was a 100% concordance rate for LOH between cytologic and histologic material, with at least 7 of the 10 cytologic samples originating from metastatic lesions and all of the surgical material originating from the primary adrenal neoplasm. CONCLUSIONS: The results of this study suggest that the combination of microdissection and PCR for LOH of p53, 1p, and 3p25 from FNA material has the potential to be utilized to distinguish ACCA from benign ACL in informative cases. It also shows a 100% concordance rate between metastatic and primary ACCAs for the losses observed, a finding that can be extremely useful for the definitive identification of metastatic lesions. Archival cytologic preparations of ACCA are a reliable source of DNA for LOH studies. [See editorial counterpoint on pages 173-5 and reply to counterpoint on pages 176-7, this issue.] Cancer (Cancer Cytopathol)

The Tall cell variant of papillary carcinoma of the thyroid: cytologic features and loss of heterozygosity of metastatic and/or recurrent neoplasms and primary neoplasms.

BACKGROUND: The Tall cell variant of papillary carcinoma of the thyroid (TCV) is characterized by the proliferation of oxyphilic, tall, columnar cells with a height-to-width ratio of at least 2:1. TCV exhibits more aggressive clinical behavior than conventional thyroid papillary carcinoma (CPC). Cytologic features suggestive of TCV have been described in fine-needle aspiration material from primary tumors. Similarly, loss of heterozygosity (LOH) for chromosome 1 (D1S243) and the p53 gene (TP53) have been reported in TCV but not in CPC, thus making exploitation of this genetic feature a potential tool for molecular discrimination between these two neoplasms. METHODS: Cytology samples of metastatic and/or recurrent neoplasms (M/R) (12 cases) and 7 cases of primary TCV obtained from 12 patients were evaluated. The cytologic findings of these cases were compared with previously published findings. Microdissection and polymerase chain reaction for LOH for chromosome 1 and p53 (D1S243 and TP53 markers) were performed on cytologic smears from 6 cases of M/R tumors and 3 cases of primary tumors. RESULTS: More then 50% of M/R showed atypical follicular cells with enlarged nuclei, granular chromatin, nuclear grooves, pseudoinclusions, and abundant finely granular cytoplasm. Cells were disposed in monolayers (58%) and papillary clusters (50%). Similar findings were present in cases of primary TCV. LOH studies showed that 4 of 6 M/R were noninformative and 2 of 3 cases of primary TCV were informative for the D1S243 marker; however, in contrast with previously published reports, no LOH was detected for the markers evaluated. CONCLUSIONS: M/R and primary TCV have similar cytologic features. Additional studies of larger series of M/R and primary TCV should be performed to delineate further any potential application of LOH for chromosome 1 and the p53 gene as a tool for diagnosing TCV with cytologic preparations. Cancer (Cancer Cytopathol)