Optimization of an immunostaining protocol for the rapid intraoperative evaluation of melanoma sentinel lymph node imprint smears with the 'MCW melanoma cocktail'

Immunocytochemistry of effusion fluids: Introduction to SCIP approach

Due to the remarkably wide morphologic spectrum of reactive mesothelial cells, some of the effusion fluids may be difficult to interpret with objective certainty by cytomorphology alone. Cytomorphology of well to moderately differentiated adenocarcinomas (responsible for the bulk of malignant effusions) may overlap with floridly reactive mesothelial cells. Even mesotheliomas including diffuse malignant epithelioid mesothelioma, are usually cytomorphologically bland without unequivocal features of malignancy. The intensity of challenge depends on the interpreter's training or experience level, institutional demographics of patients (such as type of prevalent diseases, predominant sex and age group), technical support, and quality of cytopreparatory processing. In general immunocytochemistry is valuable adjunct to facilitate objective interpretation with or without other ancillary techniques as indicated. An increasing number of immunomarkers is further refining the contribution of immunohistochemistry to this field. However, application of immunohistochemistry to effusion fluids is relatively challenging because of many variables. Multiple factors such as delay after specimen collection, specimen processing related factors including fixation and storage; ambient conditions under which paraffin blocks are archived (for retrospective testing); antigen retrieval method; duration of antigen retrieval step; antibody clone and dilution; and antibody application time are identical to application of immunohistochemistry in other areas. The significant challenge related to the potential compromization of the immunoreactivity pattern due to exposure to non-formalin fixatives / reagents is also applicable to effusion fluid specimens. The immunoreactivity results would be compared and corelated with cumulative metadata based on the reported studies performed and validated on formalin-fixed paraffin-embedded tissue sections. Deviating from such protocols may lead to suboptimal results, which is not uncommon in clinical practice with potential compromization of patient care and related liability. Because of this, it is critical to perform immunocytochemistry on formalin-fixed cell-block sections only. In addition, unless the interpretation criteria for immunohistochemical evaluation of effusion fluids are not modified specifically, it may not be productive in resolving some challenging cases. However, this aspect is not well elaborated in the literature. A basic and critical challenge is finding and locating the cells of interest in cell-block sections of effusion fluids. A unique approach is to choose a fundamental immunopanel which highlight the mesothelial and inflammatory cells in reactive effusion fluids to create the basic map. This allows detection of a 'second-foreign' population which can be immunocharacterized further with the help of subtractive coordinate immunoreactivity pattern (SCIP) approach elaborated here.

Immunocytochemistry of effusions: Processing and commonly used immunomarkers

Definitive cytopathological interpretation of some of the effusion fluids may not be possible based on cytomorphological evaluation alone. As discussed in other reviews, this is due to various reasons specifically applicable to effusion fluids including remarkably wide morphologic spectrum of reactive mesothelial cells overlapping with some well to moderately differentiated metastatic carcinoma. The challenge is subject to various factors including level of interpreter training or experience, institutional demographics (such as type of prevalent diseases, predominant sex and age group), technical advances in ancillary support, and expertise in cytopreparatory processing. In such cases immunohistochemistry performed on cell-block sections is simple objective adjunct with or without other ancillary techniques. Ongoing increase in number of immunomarkers along with rabbit monoclonal antibodies with relatively higher affinity is further refining this field. SCIP (subtractive coordinate immunoreactivity pattern) approach, discussed as separate dedicated review article, facilitates refined interpretation of immunoreactivity pattern in coordinate manner on various serial sections of cell-blocks. However, many variables such as delay after specimen collection, specimen processing related factors including fixation and storage; ambient conditions under which paraffin blocks are archived (for retrospective testing); antigen retrieval method; duration of antigen retrieval step; antibody clone and dilution; and antibody application time are common with application of immunohistochemistry in other areas. This review is dedicated to highlight technical aspects including processing of effusion specimens for optimum immunocytochemical evaluation along with commonly used immunomarkers in effusion cytopathology. This review focuses on the technical and general information about various immunomarkers.

Immunochemistry in the work-up of mesothelioma and its differential diagnosis and mimickers

The differential diagnosis in cellular effusions with cytological atypia often includes malignant mesothelioma (MM), reactive mesothelial proliferation, and malignancies of metastatic origin, particularly carcinomas. The International Reporting System for Serous Fluid recently established guidelines for reporting MM. In conjunction with the cytomorphologic evaluation, the role of immunochemistry (IC) was emphasized as a very useful tool in the workup of serous fluids, especially with the availability of novel markers. Utilizing a panel of markers, IC allows the characterization of the cells, whether mesothelial or not, and when mesothelial origin is established, IC can frequently assist in delineating its benign or malignant nature. IC can also confirm metastatic disease, allowing the identification of the primary origin in most cases. This review summarizes the current status of IC and its role in the diagnosis of MM and its differential diagnosis in serous fluids.

MCW melanoma cocktail for the evaluation of micrometastases in sentinel lymph nodes of cutaneous melanoma

Prevailing reports support the status of sentinel lymph node biopsy as the standard of care in the management of cutaneous melanoma. However, the evaluation of sentinel lymph nodes for melanoma metastases with traditionally used immunomarkers such as S100 protein and HMB45 has proved challenging. The MCW melanoma cocktail (a mixture of MART-1 [1:500], Melan-A [1:100] and tyrosinase [1:50] monoclonal antibodies) has demonstrated a highly discriminatory immunostaining pattern. Contrary to conventionally used immunomarkers such as S100 protein, the MCW melanoma cocktail facilitates detection of even singly scattered melanoma cells in sentinel lymph nodes, not only in permanent sections but also in imprint smears.

Two-color immunocytochemistry for evaluation of effusion fluids for metastatic adenocarcinoma

Background:

The evaluation of serous fluids by conventional one color immunocytochemistry is complex and challenging.

Design:

We selected and studied 37 serous fluid cytology specimens (23 pleural, 13 peritoneal, 1 pericardial), collected over a 4-year period. They were unequivocally positive for metastatic adenocarcinoma based on clinical correlation, cytomorphology, and one color immunocytochemistry on cell block sections. 3 μm serial sections of cell blocks were immunostained by a two chromogen method (peroxidase with brown chromogen followed by alkaline phosphatase with red chromogen). Combinations evaluated were: A- vimentin followed by cytokeratin (CK) 7; B- calretinin followed by BerEP4, C- calretinin followed by CK 20. Additionally, difficulty of interpretation was evaluated on a scale of 1(easy) to 5 (difficult). Cases demonstrating decreased or complete loss of immunoreactivity with alkaline phosphatase red chromogen system were also evaluated with routine one color immunostaining by alkaline phosphatase and peroxidase individually. The pretreatments for antigen retrieval and antibody dilutions were identical to those used for conventional one color immunostaining with respective immunomarker.

Result:

Combination ‘A’ showed correlation with the immunoreactivity pattern observed with one color immunostaining. However, the immunoreactivity of the second immunomarker was compromised in combinations B and C. In the latter group, the sections immunostained with one color alkaline phosphatase indicator system also showed weak immunoreactivity or complete loss of immunoreactivity for the corresponding second immunomarker. However, the peroxidase system showed proper immunoreactivity for those immunomarkers. Average difficulty of interpretation for the two color method was 1.06 (range- 1 to 2) as compared to 2.95 (range: 1 to 5) with the one color method. This difference was statistically significant (two-tailed P<.0001, paired t test). The higher scores of difficulty were observed in cases with a paucity of tumor cells and cases with predominance of isolated tumor cells.

Conclusion:

Dual immunostaining facilitated identification of the foreign population of malignant cells in effusion fluids with objective, reproducible precision. However, due to relatively lower sensitivity of alkaline phosphatase as a second indicator system, immunoreactivity was diminished for BerEP4 and lost for CK 20.

Evaluation of sentinel lymph nodes for melanoma metastases by pathologists

The pathologic evaluation of sentinel lymph nodes for melanoma metastases is not without significant challenges. It is affected by significant variation in approaches, which may compromise the final interpretation, leading to nonrepresentative spurious results. This article discusses various approaches along with recommended dos and don'ts for optimum evaluation of sentinel lymph nodes for melanoma metastases.

The 20-minute rapid MART-1 immunostain for malignant melanoma frozen sections

BACKGROUND

Immunohistochemical staining has been used to help detect malignant melanoma on Mohs surgery frozen sections. Previous investigators have developed protocols for reliable MART-1 immunostaining of frozen sections, but these protocols are time-consuming.

OBJECTIVE

The objective was to report a rapid 20-minute MART-1 immunostaining protocol for frozen sections.

METHODS

The protocol was utilized on 30 melanomas treated with Mohs micrographic surgery.

RESULTS

The stain clearly highlighted normal background melanocytes, as well as melanocytic hyperplasia and malignant melanoma.

CONCLUSIONS

The 20-minute protocol provides a rapid and reliable method for immunostaining of malignant melanoma. The availability of more rapid immunostaining methods improves efficiency of the Mohs laboratory and significantly reduces patient and physician waiting time. The authors have indicated no significant interest with commercial supporters.

Prevention of an additional surgery for regional lymphadenectomy in melanoma: rapid intraoperative immunostaining of sentinel lymph node imprint smears

Background

Sentinel lymph node (SLN) biopsy is performed at many institutions and is considered a standard of care in the management of cutaneous melanoma. The discriminatory immunostaining pattern with the 'MCW Melanoma Cocktail' (a mixture of MART-1 {1:500}, Melan- A {1:100}, and Tyrosinase {1:50} monoclonal antibodies) allows intraoperative immunocytochemical evaluation of imprint smears of SLNs for melanoma metastases. Cohesive cells of benign capsular melanocytic nevi that were also immunoreactive with the cocktail do not exfoliate easily for imprint smear detection.

Methods

We prospectively evaluated 73 lymph nodes (70 SLN & 3 non-SLN) from 41 cases (mean 1.8, 1 to 4 SLNs/case) of cutaneous melanoma using a rapid 17-minute immunostaining previously published protocol. The results were compared with permanent sections also immunostained with 'the cocktail'.

Results

19.5%, 8/41 cases (12%, 9/73 lymph nodes) were positive for melanoma metastases on permanent sections immunostained with the 'MCW melanoma cocktail'. Melanoma metastases in 87.5% (7/8) of these cases were also detected in rapidly immunostained imprint smears, with 100% specificity and 90% sensitivity. None of the 7 SLNs from 7 cases with capsular nevi showed false positive results.

Conclusion

Melanoma metastases could be detected in imprint smears immunostained with 'MCW Melanoma Cocktail' utilizing a rapid intraoperative protocol. The cohesive cells of the capsular nevi do not readily exfoliate and do not lead to false positive interpretation. In a majority of positive cases, a regional lymphadenectomy could have been completed during the same surgery for SLN biopsy and wide excision of primary melanoma site, potentially eliminating the need for an additional surgery.

First CytoJournal Peer-Reviewer's Retreat in 2006 - open access, peer-review, and impact factor

CytoJournal organized its first Peer-Reviewer's Retreat of 2006 during the United States and Canadian Academy of Pathology Annual Meeting at Atlanta on Feb 12, 2006. The major topics discussed were open access, peer review, and impact factors. Representative participants volunteered to join the task force to prepare an instructional guide for peer-reviewing cytopathology manuscripts. Concern about the impact factor for CytoJournal was discussed. A feedback to its readers and authors was recommended. Impact factor calculation needs at least three years of journal statistics. It is only possible after two years from the time a journal is first accepted by Thomson-ISI for citation tracking. CytoJournal is still too new for an impact factor to be calculated. However, general progress of CytoJournal suggests an encouraging pattern for high impact factor.

CytoJournal's move to fund Open Access

CytoJournal is published by an independent publisher BioMed Central, which is committed to ensuring that the peer-reviewed biomedical research is Open Access. Since its launch, BioMed Central has graciously supported the processing of all the articles published during CytoJournal's first 6 months. However, for long term viability, CytoJournal has to achieve financial viability to support publication expenses. From 1st March, 2005, authors will be asked by the publisher to pay a flat article-processing charge. This editorial discusses how a significant proportion of authors may not have to pay this fee directly under a variety of different mechanisms such as institutional and society memberships with BioMed Central.