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.

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.

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.

Anti-alpha-inhibin: marker of choice for the consistent distinction between adrenocortical carcinoma and renal cell carcinoma in fine-needle aspiration.

BACKGROUND: Anti-alpha-inhibin, an antibody directed against a peptide hormone, has been shown to be a useful diagnostic aid in surgical pathology material for the identification of sex cord-stromal neoplasms and recently has been described in adrenocortical carcinoma (ACC). The diagnosis of ACC versus renal cell carcinoma (RCC) may be difficult morphologically, particularly in fine-needle aspiration (FNA) material. To date, the immunohistochemical distinction of ACC from RCC is based on a panel of antibodies that include vimentin, cytokeratins, and epithelial membrane antigen. However, the reliability of this panel is weakened by inconsistent staining patterns. METHODS: Archival formalin fixed, paraffin embedded cell block sections from 45 FNAs of known primary and metastatic ACC and RCC as well as benign adrenocortical nodules were stained with anti-alpha-inhibin using an avidin-biotin procedure. All samples were microwave pretreated and a biotin block was performed to reduce the background stain due to the high endogenous biotin often present in these types of samples. RESULTS: All cases of ACC (n = 7; 100%) and benign adrenocortical cells (n = 15; 100%) were immunoreactive with the a-inhibin antibody, showing a diffuse cytoplasmic and granular staining pattern. The staining intensity and number of immunoreactive cells varied within each sample, with the cases of ACC having the greatest proportion of immunoreactive cells and the strongest intensity. None of the cases of RCC (n = 23; 0%) were immunoreactive with anti-alpha-inhibin. CONCLUSIONS: The morphologic distinction of ACC versus RCC in FNA material from renal, adrenal, and metastatic neoplasms is not always feasible based on cytology alone. However, due to the advent of the alpha-inhibin antibody, the reliable distinction of these entities now may be possible. The intense and specific immunostaining pattern for cells of adrenal origin, even in paucicellular samples, suggests potential for the widespread clinical utility of this marker by cytopathologists.

Melanoma-associated antigen recognized by T cells (MART-1): the advent of a preferred immunocytochemical antibody for the diagnosis of metastatic malignant melanoma with fine-needle aspiration.

BACKGROUND: HMB-45, an antibody directed against a premelanosome glycoprotein, has thus far been considered the most specific antibody for the immunocytochemical substantiation of the diagnosis of malignant melanoma (MM). A recently described antigen, MART-1, is a transmembrane protein that is present in normal melanocytes and widely expressed in MM. Antibodies to MART-1 have recently become commercially available. Both HMB-45 and MART-1 form the basis of ongoing immunotherapy protocols at the National Institutes of Health/National Cancer Institute. METHODS: The authors evaluated 207 lesions from 160 patients with metastatic MM procured via fine-needle aspiration (FNA) for expression of MART-1 (clone M2-7C10) and HMB-45 prior to commencement of immunotherapy. FNAs were performed on subcutaneous soft tissue masses (190 lesions), lung (8 lesions), liver (5 lesions), pancreas (3 lesions), and brain (1 lesion). To test the specificity of the monoclonal antibody directed against MART-1, the authors evaluated its reactivity in normal tissues as well as in various nonpigmented neoplasms that are often included in the differential diagnosis of MM. RESULTS: Of all lesions tested, 13 (6%) were negative for both MART-1 and HMB-45. Of all patients tested, 20% had 1 or more lesions that were non-immunoreactive with HMB-45, whereas only 10% had 1 or more lesions that were nonimmunoreactive for MART-1. Eight percent of the lesions tested were negative for MART-1 only, whereas 16% of lesions tested were negative for HMB-45 only. In 35% of the lesions, MART-1 stained more cells than HMB-45. In 13%, MART-1 stained fewer cells than HMB-45, and in 52% both antibodies stained an equivalent number of cells. All samples of normal tissue were negative for staining with MART-1, as were the nonpigmented lesions tested. Melanocytes in normal skin samples stained positively for MART-1. CONCLUSIONS: The MART-1 antibody is a superior immunohistochemical marker for the diagnosis of MM. It has the potential to become the preferred antibody over HMB-45 for the diagnosis of metastatic MM in FNA material, as MART-1 stains a higher percentage of lesions in a higher percentage of patients than does HMB-45.

Comparison of melanoma antigen recognized by T cells (MART-1) to HMB-45: additional evidence to support a common lineage for angiomyolipoma, lymphangiomyomatosis, and clear cell sugar tumor.

The antibody to the melanoma antigen recognized by T cells (anti-MART-1, clone M2-7C10) is a newly described antibody to a transmembrane protein previously detected only in normal skin melanocytes, retinal tissue, and malignant melanoma (MM). This antibody is the basis for ongoing immunotherapy protocols at the National Institutes of Health/National Cancer Institute. HMB-45, an antibody directed against a premelanosome glycoprotein, although used predominantly for the diagnosis of MM, has shown consistent staining in angiomyolipoma (AML), lymphangiomyoma/lymphangiomyomatosis (LAM), and clear cell sugar tumor (CCST), a group of tumors proposed to be related on the basis of their common perivascular epithelioid cells, which exhibit various degrees of smooth muscle differentiation, melanogenesis, and intracytoplasmic membrane bound granules. To compare the immunoreactive patterns of anti-MART-1 with those of HMB-45, we performed avidin-biotin immunoperoxidase testing on nonmelanocytic neoplasms (AMLs, LAMs, CCSTs) known to express HMB-45. Microwave pretreatment was necessary for anti-MART-1 staining on paraffin-embedded material. Our results showed that all of the 10 cases of AML were immunoreactive for both anti-MART-1 and HMB-45; that all of the 4 cases of LAM were positive for HMB-45, with 1 of the 4 reacting with anti-MART-1; and that 3 of the 4 cases of CCST expressed HMB-45, whereas 1 of the 4 was positive for anti-MART-1. Our findings lent additional support to previous studies that proposed a relationship between AML, LAM, and CCST. Anti-MART-1 and HMB-45 share similar specificities for these nonmelanocytic tumors, but the former seems to be a less sensitive marker for these lesions. In similar circumstances, anti-MART-1 and HMB-45 are potentially useful clinical markers.

Utility of the antibodies CA 19-9, HBME-1, and thrombomodulin in the diagnosis of malignant mesothelioma and adenocarcinoma in cytology.

BACKGROUND: The distinction between malignant mesothelioma (MM) and adenocarcinoma (ACA) in cytologic specimens frequently is difficult, often requiring immunocytochemistry to support the diagnosis. Recent reports have proposed the utilization of antibodies to mesothelial cell clone HBME-1 and thrombomodulin (TM), because they are immunoreactive in MM and less commonly reactive in ACA. Immunoreactivity for the monoclonal antibody CA 19-9 has been observed in many ACAs and reportedly is absent in MM. METHODS: In this study, immunostaining was performed on formalin fixed, paraffin embedded cell blocks from effusions or fine-needle aspirations using the avidin-biotin-peroxidase method. Thirty-eight MMs and 49 ACAs were tested using antibodies to CA 19-9, HBME-1, and TM. RESULTS: Anti-CA 19-9 stained only 1 of the 37 cases of MM tested (3%), but stained 24 of the 49 cases of ACA (49%). Anti-HBME-1 stained 34 of 38 cases of MM (89%), and 28 of 43 cases of ACA tested (65%). Anti-TM stained 24 of 36 cases of MM (67%), and 21 of 40 cases of ACA tested (53%). CONCLUSIONS: CA 19-9 has utility as part of an immunocytochemical panel for distinguishing ACA from MM, because a positive staining reaction would make the diagnosis of MM unlikely. Although HBME-1 and TM can identify MM positively, each frequently is detected in ACA, thus limiting the utility of these antibodies in cytologic specimens.

Immunocytochemical detection of MART-1 in fresh and paraffin-embedded malignant melanomas.

MART-1 is a transmembrane protein that appears to be melanocyte specific. This study evaluated the use of a new monoclonal antibody, directed against MART-1, in fresh and paraffin-embedded specimens. Twenty-three paraffin-embedded tumors were evaluated for MART-1 immunoreactivity both before and after microwave-based antigen retrieval. After this comparison, 53 fine-needle aspirates from 43 patients with malignant melanoma were assessed for MART-1 immunoreactivity. Immunocytochemistry was performed on both cytospins and paraffin-embedded tissues that were pretreated with antigen retrieval. Seventeen (74%) of 23 tumors evaluated for immunoreactivity before and after antigen retrieval showed a significant increase in both staining intensity and the number of cells stained. When cytospins and antigen-retrieved cell blocks from 53 fine-needle aspirates were compared. 38 (72%) showed good correlation. In 13 (25%) of 53 tumors, MART-1 immunoreactivity was more intense in the cytospins, although the differences were marked in only two cases: Microwave-based antigen retrieval renders paraffin-embedded tissues nearly as sensitive as fresh material for use in the immunocytochemical detection of MART-1. This technique will allow the evaluation of MART-1 immunoreactivity in archival malignant melanomas.

Phase I crossover study of paclitaxel with r-verapamil in patients with metastatic breast cancer.

PURPOSE: We conducted a phase I crossover study of escalating doses of both paclitaxel (Taxol; Bristol-Myers, Squibb, Princeton, NJ) and r-verapamil, the less cardiotoxic stereoisomer, in heavily pretreated patients with metastatic breast cancer. PATIENTS AND METHODS: Twenty-nine patients refractory to paclitaxel by 3-hour infusion were treated orally with r-verapamil every 4 hours starting 24 hours before the same-dose 3-hour paclitaxel infusion and continuing for a total of 12 doses. Once the maximum-tolerated dose (MTD) of the combination was determined, seven additional patients who had not been treated with either drug were evaluated to determine whether the addition of r-verapamil altered the pharmacokinetics of paclitaxel. Consenting patients had tumor biopsies for P-glycoprotein (Pgp) expression before receiving paclitaxel and after becoming refractory to paclitaxel therapy. RESULTS: The MTD of the combination was 225 mg/m2 of r-verapamil every 4 hours with paclitaxel 200 mg/m2 by 3-hour infusion. Dose-limiting hypotension and bradycardia were observed in three of five patients treated at 250 mg/m2 r-verapamil. Fourteen patients received 32 cycles of r-verapamil at the MTD as outpatient therapy without developing cardiac toxicity. The median peak and trough serum verapamil concentrations at the MTD were 5.1 micromol/L (range, 1.9 to 6.3), respectively, which are within the range necessary for in vitro modulation of Pgp-mediated multidrug resistance (MDR). Increased serum verapamil concentrations and cardiac toxicity were observed more frequently in patients with elevated hepatic transaminases and bilirubin levels. Hematologic toxicity from combined paclitaxel and r-verapamil was significantly worse compared with the previous cycle of paclitxel without r-verapamil. In the pharmacokinetic analysis, r-verapamil delayed mean paclitaxel clearance and increased mean peak paclitaxel concentrations. CONCLUSION: r-Verapamil at 225 mg/m2 orally every 4 hours can be given safely with paclitaxel 200 mg/m2 by 3-hour infusion as outpatient therapy and is associated with serum levels considered active for Pgp inhibition. The addition of r-verapamil significantly alters the toxicity and pharmacokinetics of paclitaxel.

Characteristics of nine newly derived mesothelioma cell lines.

This report characterizes nine new cell lines derived from patients with malignant pleural mesothelioma. The lines were initiated between July 1990 and July 1992 from solid tumors (5 lines) or effusions (4 lines) and had proliferated for a period of at least 2 months without senescence. They were characterized by cell size, doubling time, immunohistochemical analyses, electron microscopy, and chromosomal karyotyping. Growth factor/cytokine elaboration was determined using enzyme-linked immunoassays. The established lines were similar in morphology to their parent tumor (ie, epithelial or sarcomatoid). Cell sizes ranged from 59 to 81 microns, and the doubling times varied from 31 to 65 hours. The lines stained with cytokeratin and showed expected negative staining for adenomarkers including B72.3 and carcinoembryonic antigen. All cell lines exhibited aneuploidy, with modal chromosome numbers between 40 and 81 and had multiple chromosomal aberrations. Significant production of granulocyte-monocyte colony-stimulating factor, leukemia inhibitory factor, platelet-derived growth factor, and interleukin-6 was seen. These new cell lines derived from human mesotheliomas can now be used to aid in the design of innovative treatment strategies.