Christopher N. Otis

Pleomorphic lobular carcinoma: morphology, immunohistochemistry, and molecular analysis.

Infiltrating pleomorphic lobular carcinoma (PLC) is an aggressive variant of infiltrating lobular carcinoma. Recently, in situ changes identical to PLC (PLCIS) have been described. The role of prognostic markers and their correlation with therapeutics, clinical outcome, and genetic changes is not well established in PLC. The authors examined 38 cases of this entity to understand better this tumors biology. Immunohistochemical (IHC) analysis was performed in 21 specimens for estrogen and progesterone steroid receptors, p53, Her 2 (p185), and GCDFP-15. Genomic deoxyribonucleic acid was obtained from microdissected tumor as well as normal control cells, and loss of heterozygosity was investigated at the ESR (16q24), p53 (TP53 17p), Her 2 (17q 11-12), and BRCA 1 (17q12-25) loci. In this series, the average patient age was 57.5 years (age range, 24–92 years). Twenty-seven women were postmenopausal. Tumor size ranged from 1.2 to 25 cm. Six patients were a pathologic stage I; 19, stage II; 12, stage III; and one, stage IV. Histologically, multifocal nodular aggregates of discohesive pleomorphic tumor cells were seen interspersed in dense and fibrotic breast parenchyma. Twenty-nine percent of the specimens demonstrated associated signet ring cells. The remainder had dishesive, globoid, plasmacytoid cells with high-grade nuclear features. PLCIS was identified in 17 of 38 patients (45%), and lobular carcinoma in situ (LCIS) was noted in 8 patients (21%). IHC analysis showed estrogen immunoreactivity in 81%, progesterone in 67%, GCDFP-15 in 71%, and Her 2 in 81% (2+ to 3+ membranous staining) of specimens. Antibodies to p53 stained the tumor cell nuclei in 48% of the tumors. Loss of heterozygosity was identified in 52% of the specimens at the p53 locus, 18% at the ESR locus, 19% to 24% at the Her 2 loci, and 27% to 32% at the BRCA 1 locus. Follow-up was available in 19 patients and ranged from 12 months to 15 years (mean, 73 months). Seven patients had no evidence of disease at last examination (range, 1–15 years), three patients were alive with disease (range, 2–14 years), and nine patients were dead of disease (range, 2 months–9 years). Six patients had subsequent diagnoses of tumor in the contralateral breast. Analysis shows that PLC tends to appear in older postmenopausal women who present with locally advanced disease. PLCIS was found to be associated with PLC 45% of the time. The aggressive clinical course of patients with PLC is supported by tumor immunoreactivity with unfavorable markers Her 2 and p53. Overexpression of Her 2 in PLC may be therapeutically relevant, enabling the use of novel chemotherapeutic drugs like Herceptin. Interestingly, tumors that were Her 2 immunoreactive also maintained estrogen hormone immunoreactivity.

Immunohistochemical evaluation of pleural mesothelioma and pulmonary adenocarcinoma. A bi-institutional study of 47 cases

Pleural mesotheliomas and peripheral pulmonary adenocarcinomas were evaluated by immunohistochemistry at two institutions (Yale University School of Medicine and the City of Hope National Medical Center). Twenty-three mesotheliomas, 11 with ultrastructural verification, and 24 pulmonary adenocarcinomas were studied. Antikeratin, anticarcinoembryonic antigen, anti-human milk fat globule related antigen, MC-1, B72.3, and Leu M-1 antibodies were employed. The immunohistochemistry of each case prepared at one institution was reviewed at the other. As groups, the two tumor types were distinguishable using this antibody panel. Essentially, mesotheliomas were keratin positive only. The adenocarcinomas were positive for CEA, MFG, B72.3, and Leu M-1. However, there were some ambiguities presented by the immunohistochemistry. The higher molecular weight keratins were found in most but not all mesotheliomas and in only a few adenocarcinomas. Lower molecular weight keratins were positive not only in all the mesotheliomas, but also in the adenocarcinomas. CEA was found not only in nearly all the adenocarcinomas, but also in a tumor determined by electron microscopy to be mesothelioma. Preabsorption of CEA decreased the sensitivity for adenocarcinoma, but did not change the positivity of the putative mesothelioma. B72.3 and Leu M-l were specific for adenocarcinoma, but were found in only half of them. The MFG was apparently specific for adenocarcinoma, but the findings were difficult to interpret. At the level of individual cases, greater sensitivity of separation can be achieved by combining the results of two or more antibodies, but the lack of a detectable specific antigen in mesothelioma continues to make some cases difficult to evaluate by immunohistochemistry alone.

The rapid onset of cutaneous angiosarcoma after radiotherapy for breast carcinoma

Malignant neoplasms known to develop following external beam radiation include squamous cell carcinoma, osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma, mixed mullerian tumors, malignant schwannoma, myelogenous leukemia and angiosarcoma. Latency periods of many years characterize the onset of these tumors following the exposure. Cutaneous angiosarcoma following radiotherapy for breast carcinoma has been rarely documented, occurring up to 13 years postirradiation. Two cases of this entity are reported occurring 37 months postradiotherapy at the site of mastectomy performed for mammary duct carcinoma.

Nd:YAG laser excision of a giant gingival pyogenic granuloma of pregnancy

A 19‐year‐old Hispanic nullipara experienced the rapid growth of an oral lesion on the right lower gingiva which she had first noticed at 29 weeks gestation. The lesion interfered with oral hygiene and eating. At surgery, the lesion measured 3.5 × 2.5 × 2.0 cm. Biopsy confirmed a pyogenic granuloma (“granuloma gravidarum”). Panorex films showed no bony invasion. The lesion was excised using the Nd:YAG laser under general anesthesia when the patient had reached 36 3/7 weeks gestation. We chose the Nd:YAG laser over the CO2 laser for the removal of this very vascular lesion, because of its superior coagulation characteristics. This technique results in removal of the lesion with less danger of bleeding than with any other surgical technique. The patient did well postoperatively, delivered a healthy 3,884 g infant at 40 6/7 weeks gestation, and has had no recurrence after 15 months of follow‐up.

Three types of spindle cell tumors of the pleura. Fibroma, sarcoma, and sarcomatoid mesothelioma

The clinicopathologic features of 17 fibrous tumors of the pleura are presented. Eight were benign localized fibrous tumors; all of these were negative when stained with antibodies to keratin. Eight were diffuse malignant tumors that demonstrated intense immunohistochemical staining of the spindle cells with antibodies to keratin. One case presented as a histologically malignant spindle cell tumor that was initially localized but recurred subpleurally three times in 12 years. This spindle cell tumor was consistently negative when stained for keratin. We conclude that there are three types of fibrous tumors of the pleura: (a) a localized, histologically benign, keratin-negative spindle cell tumor that might be termed “fibroma,” (b) a diffuse, histologically malignant, keratin-positive neoplasm that might appropriately be termed a “sarcomatoid mesothelioma,” and (c) a histologically malignant, keratin-negative, spindle cell tumor with the potential to spread under the pleura that might appropriately be termed a “sarcoma.” Immunohistochemistry proved to be useful in distinguishing the sarcomatoid mesothelioma from the sarcoma.

Use of an Aggressive MCF-7 Cell Line Variant, TMX2-28, to Study Cell Invasion in Breast Cancer

An estrogen receptor–negative variant of the MCF-7 breast cancer cell line, TMX2-28, was used as a model in which to study breast cancer cell invasion. Using a reconstituted basement membrane (Matrigel) assay to evaluate cell invasion, we determined that TMX2-28 cells are more invasive than MCF-7 cells and that the invasiveness of TMX2-28 is similar to that of the aggressive MDA-MB-231 breast cancer cell line. TMX2-28 cells displayed a rounded, epithelial cell–like morphology, suggesting an amoeboid mode of cell invasion, in contrast to the mesenchymal mode of invasion characteristic of spindle-shaped, fibroblast-like MDA-MB-231 cells. Using real-time reverse transcription-PCR, we found that mitogen-inducible gene 2 (MIG2) is expressed at a 17-fold higher level in TMX2-28 cells than in nonaggressive MCF-7 cells and that MIG2 mRNA levels are low in the nontumorigenic human mammary epithelial cell line, 184. We determined that MIG2 plays a role in cell invasion by using small interfering RNA (siRNA) to suppress the expression of MIG2 mRNA levels in TMX2-28 cells. TMX2-28 cell invasion was reduced by 48% when the cells were transfected with siRNAs targeting MIG2, relative to cells transfected with siRNAs against glyceraldehyde-3-phosphate dehydrogenase. Finally, MIG2 expression was evaluated in reductive mammoplasty and breast tumor tissue. Although all 21 normal tissues from reduction mammoplasty showed immunoreactivity for MIG2, ranging from weak (62%) to strong (24%), only half of the 34 formalin-fixed breast tumors showed immunoreactivity for MIG2. Of these 17 positive cases, 10 were considered to overexpress MIG2 (moderate to strong staining). Examination of 30 frozen breast tumors supported the finding that MIG2 is overexpressed in a subset of breast cancers. We suggest that MIG2s normal regulation and function are disrupted in breast cancer. (Mol Cancer Res 2006;4(12):905–13)

Intermediate Filamentous Proteins in Adult Granulosa Cell Tumors: An Immunohistochemical Study of 25 Cases

Adult granulosa cell tumors (AGCTs) are classified as sex cord-stromal tumors of the ovary. However, they may be confused with other primary ovarian neoplasms. Intermediate filaments, specifically vimentin and cytokeratins, have been identified in AGCTs by immunohistochemistry performed on frozen and formalin-fixed, paraffinembedded tissue and two-dimensional electrophoresis. Recently, however, immunohistochemical demonstration of cytokeratin has been used as supporting evidence of epithelial rather than sex cord-stromal differentiation in ovarian neoplasia. To investigate further intermediate filamentous proteins in AGCTs, 25 such tumors were studied by immunohistochemistry in formalin-fixed, paraffinembedded sections. Cytoplasmic staining was observed, frequently in a distinct punctate, paranuclear pattern, in 14 of 25, 14 of 25, and seven of 17 tumors using monoclonal antibodies AE1/AE3, CAM 5.2, and 35BH11, respectively, which share the ability to detect low molecular weight cytokeratins. Staining for cytokeratin was not seen in any of the 17 tumors studied using the antibody 34BE12. Twenty-three of 25 tumors showed strong positivity for vimentin, characteristically seen as globoid paranuclear staining. Nine of 25 tumors contained desmin, which was restricted to the intermixed spindle cell, cortical type stromal component of the tumors. These patterns of immunoreactivity for intermediate filaments, particularly cytokeratins, are different than in common epithelial tumors of the ovary and may be useful in the differential diagnosis of ovarian neoplasia. Moreover, the immunohistochemical detection of cytokeratins should not be used as a criterion for excluding AGCT from the differential diagnosis of an ovarian neoplasm.

Loss of Heterozygosity Occurs via Mitotic Recombination in Trp53+/− Mice and Associates with Mammary Tumor Susceptibility of the BALB/c Strain

Loss of heterozygosity (LOH) occurs commonly in cancers causing disruption of tumor suppressor genes and promoting tumor progression. BALB/c-Trp53+/− mice are a model of Li-Fraumeni syndrome, exhibiting a high frequency of mammary tumors and other tumor types seen in patients. However, the frequency of mammary tumors and LOH differs among strains of Trp53+/− mice, with mammary tumors occurring only on a BALB/c genetic background and showing a high frequency of LOH, whereas Trp53+/− mice on a 129/Sv or (C57BL/6 × 129/Sv) mixed background have a very low frequency of mammary tumors and show LOH for Trp53 in only ∼50% of tumors. We have performed studies on tumors from Trp53+/− mice of several genetic backgrounds to examine the mechanism of LOH in BALB/c-Trp53+/− mammary tumors. By Southern blotting, 96% (24 of 25) of BALB/c-Trp53+/− mammary tumors displayed LOH for Trp53. Karyotype analysis indicated that cells lacking one copy of chromosome 11 were present in all five mammary tumors analyzed but were not always the dominant population. Comparative genomic hybridization analysis of these five tumors indicated either loss or retention of the entire chromosome 11. Thus chromosome loss or deletions within chromosome 11 do not account for the LOH observed by Southern blotting. Simple sequence length polymorphism analysis of (C57BL/6 × BALB/c) F1-Trp53+/− mammary tumors showed that LOH occurred over multiple loci and that a combination of maternal and paternal alleles were retained, indicating that mitotic recombination is the most likely mechanism of LOH. Nonmammary tumors of BALB/c mice also showed a high frequency of LOH (22 of 26, 85%) indicating it was not a mammary tumor specific phenomenon but rather a feature of the BALB/c strain. In (C57BL/6 × BALB/c) F1-Trp53+/− mice LOH was observed in 93% (13 of 14) of tumors, indicating that the high frequency of LOH was a dominant genetic trait. Thus the high frequency of LOH for Trp53 in BALB/c-Trp53+/− mammary tumors occurs via mitotic recombination and is a dominant genetic trait that associates with the occurrence of mammary tumors in (C57BL/6 × BALB/c) F1-Trp53+/− mice. These results further implicate double-strand DNA break repair machinery as important contributors to mammary tumorigenesis.

Canadian Association of Pathologists-Association canadienne des pathologistes National Standards Committee/Immunohistochemistry: best practice recommendations for standardization of immunohistochemistry tests.

Immunohistochemical and immunocytochemical assays are highly complex diagnostic analyses used to aid in the accurate identification and biologic characterization of tissue types in neoplastic and nonneoplastic diseases. Immunohistochemical tests are applied mainly to the diagnosis of neoplasms. Some immunohistochemical tests provide information of important prognostic and predictive value in selected human neoplasms and, as such, are often critical for the appropriate and effective treatment of patients. This document provides recommendations and opinions of the Canadian Association of Pathologists-Association canadienne des pathologistes National Standards Committee/Immunohistochemistry relevant to clinical immunohistochemical terminology, classification of immunohistochemical tests based on risk assessment, and quality control and quality assurance and summarizes matters to be considered for appropriate immunohistochemical/immunocytochemical test development, performance, and interpretation in diagnostic pathology and laboratory medicine.

Ovarian serous borderline epithelial tumors with multiple retroperitoneal nodal involvement: Metastasis or malignant transformation of epithelial glandular inclusions?

One of four patients who underwent lymph node excision at exploration for ovarian serous borderline epithelial tumor (OSBT) at Baystate Medical Center was found to have FIGO Stage III C lesion associated with extensive ovarian external (surface) papillary growth, peritoneal implants in the omentum and cul-de-sac, and involvement of multiple pelvic and periaortic lymph nodes by the tumor. Histologically, the lymph nodes showed an admixture of endosalpingeal glandular inclusions with neoplastic tissue identical to the ovarian tumor. The exact histogenesis and the prognostic significance of the nodal involvement by OSBT are still not fully understood. Although there is a small number of reported cases of lymph node involvement associated with OSBT, they are described as examples of nodal metastases or independent primary foci of malignant transformation. This paper presents an interesting association of OSBT with extensive pelvic and periaortic nodal involvement and reviews the relevant literature.