Eduardo Eyzaguirre

Maporal Viral Infection in the Syrian Golden Hamster: A Model of Hantavirus Pulmonary Syndrome

Hantavirus pulmonary syndrome (HPS) is a severe and often fatal rodent-borne zoonosis. Maporal (MAP) virus is a newly discovered hantavirus that originally was isolated from an arboreal rice rat captured in central Venezuela. The results of this study indicate that MAP virus in the Syrian golden hamster (Mesocricetus auratus) can cause a disease that is clinically and pathologically remarkably similar to HPS. The similarities include the time course of clinical disease, presence of virus-specific IgG at the onset of clinical disease, subacute pneumonitis, rapid onset of diffuse alveolar edema in the absence of necrosis, hepatic-portal triaditis, mononuclear-cellular infiltrate in lung and liver, widespread distribution of hantaviral antigen in endothelial cells of the microvasculature of lung and other tissues, and variable lethality. These similarities suggest that the MAP virus-hamster system is a useful model for studies of the pathogenesis of HPS and for the evaluation of potential therapeutic agents.

EGFR and HER-2/neu expression in invasive apocrine carcinoma of the breast.

This study was undertaken to investigate epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER-2)/neu expression in a cohort of apocrine carcinomas of the breast with emphasis on the classification of the breast tumors with apocrine morphology. In total, 55 breast carcinomas morphologically diagnosed as apocrine were evaluated for the steroid receptor expression profile characteristic of normal apocrine epithelium (androgen receptor positive/estrogen receptor (ER) negative/progesterone receptor (PR) negative), and for the expression of EGFR and Her-2/neu proteins, and the copy number ratios of the genes EGFR/CEP7 and HER-2/CEP17. On the basis of the results of steroid receptors expression, 38 (69%) cases were classified as pure apocrine carcinoma (androgen receptor positive/ER negative/PR negative), whereas 17 (31%) were re-classified as apocrine-like carcinomas because they did not have the characteristic steroid receptor expression profile. Her-2/neu overexpression was observed in 54% of the cases (57% pure apocrine carcinomas vs 47% apocrine-like carcinomas). HER-2/neu gene amplification was demonstrated in 52% of all cases (54% pure apocrine carcinomas vs 46% apocrine-like carcinomas). EGFR protein (scores 1 to 3+) was detected in 62% of all cases and was expressed in a higher proportion of pure apocrine carcinomas than in the apocrine-like carcinomas group (76 vs 29%, P=0.006). In the pure apocrine carcinoma group, Her-2/neu and EGFR protein expression were inversely correlated (P=0.006, r=−0.499). EGFR gene amplification was observed in two pure apocrine carcinomas and one apocrine-like carcinoma. Polysomy 7 was commonly present in pure apocrine carcinomas (61 vs 27% of apocrine-like carcinomas; P=0.083) and showed a weak positive correlation with EGFR protein expression (P=0.025, r=0.326). Our study showed that apocrine breast carcinomas are molecularly diverse group of carcinomas. Strictly defined pure apocrine carcinomas are either HER-2-overexpressing breast carcinomas or triple-negative breast carcinomas, whereas apocrine-like carcinomas predominantly belong to the luminal phenotype. Pure apocrine carcinomas show consistent overexpression of either EGFR or HER-2/neu, which could have significant therapeutic implications.

Memy I: a novel murine model for uterine leiomyoma using adenovirus-enhanced human fibroid explants in severe combined immune deficiency mice

OBJECTIVE This study was undertaken to develop a representative murine model for human leiomyoma. STUDY DESIGN Human fibroid tumor tissues were cut into small pieces and treated with medium alone, adenoviral-beta-galactosidase, adenoviral-vascular endothelial growth factor-A, adenoviral-cyclooxygenase-2, or both adenoviral-vascular endothelial growth factor-A and adenoviral- cyclooxygenase-2. Tissue pieces were inserted subcutaneously in the flank of each severe combined immunodeficient mouse. The developed lesion was measured twice per week. Xenograft tissues were harvested after 30 days and analyzed. RESULTS Tissue pieces transfected with both adenoviral-cyclooxygenase-2 and adenoviral-vascular endothelial growth factor-A continued to grow up to 30 days postimplantation. The number of proliferating and apoptotic cells, as well as the expression of smooth muscle actin, desmin, vimentin, estrogen receptors, and progesterone receptors was similar between retrieved grafts from that group and the original patient tissue. Furthermore, hematoxylin and eosin and Massons Trichrome stains confirmed this similarity. CONCLUSION Human uterine leiomyoma xenografts, pretreated with both adenoviral- cyclooxygenase-2 and adenoviral-vascular endothelial growth factor-A and implanted subcutaneously in severe combined immunodeficient mice, represent a novel model for human uterine leiomyoma.

p53 Protein Expression and Gene Mutation in Phyllodes Tumors of the Breast

The malignant potential of mammary phyllodes tumors is difficult to assess on initial pathologic examination. Studies on the p53 tumor suppressor gene have shown that it has an important role in the development of a variety of malignancies, yet the specific contribution to the pathogenesis and development of the malignant potential of phyllodes tumor is largely unknown. We studied p53 protein expression in 25 cases of phyllodes tumors histologically classified as either malignant (12 cases) or benign (13 cases). Using microdissection approach, we also analyzed the p53 gene sequence in a case that demonstrated progression from benign to malignant phenotype. Nuclear p53 staining was detected in various proportions (1-90%) of neoplastic stromal cells of malignant tumors. No staining was found in benign tumors. Progression from benign to malignant phenotype was associated with a significant increase in the accumulation of p53 (more than 20 times). This was caused by an underlying missense mutation in exon 7, resulting in a change from Arg248 to Trp248 in the malignant component of the tumor. Stromal p53 over-expression was observed only in neoplasms histologically classified as malignant and was associated with an increased proliferation index (MIB-1 staining). These two markers may be used as useful adjuncts in the diagnosis of malignancy in difficult cases or when only a limited sample size is available. Somatic mutation in exon 7 of p53 gene in malignant phyllodes tumor points toward the importance of p53 in the malignant transformation of phyllodes tumors.

Diagnosis of Primary Fibrosarcoma of the Lung by Fine-Needle Aspiration and Core Biopsy A Case Report and Review of the Literature

Primary pulmonary sarcomas are uncommon neoplasms. Primary fibrosarcoma of the lung is extremely rare, and only 53 cases have been documented in the literature to date. To our knowledge, the diagnosis of primary lung fibrosarcoma by fine-needle aspiration cytology has never been reported. We report a case of pulmonary fibrosarcoma diagnosed by fine-needle aspiration cytology and core biopsy. The neoplasm consisted of interweaving fascicles of minimally atypical spindle cells with slender nuclei and scant cytoplasm. Positive immunohistochemistry for vimentin along with nonreactivity of tumor cells for keratin, S100 protein, desmin, alpha-smooth muscle actin, and CD34 supported the the diagnosis. The diagnosis was later confirmed by histologic and ultrastructural findings following lobectomy. A meticulous clinical search for a possible primary neoplasm elsewhere was unsuccessful, and lung was established as the primary site. Fine-needle aspiration cytology and core biopsy are reliable methods for establishing a diagnosis of fibrosarcoma.

Hyalinizing clear cell carcinoma of the tonsil and its treatment

Hyalinizing clear cell carcinoma (HCCC) is a rare neoplasm affecting mainly the minor salivary glands of the oral cavity. We describe an unusual case of HCCC involving the tonsil and its successful management. A 67-year-old Hispanic woman was discovered to have an asymptomatic right tonsillar mass on routine clinic visit that revealed HCCC on biopsy. A right radical tonsillectomy was performed and pathology confirmed HCCC with positive deep surgical margins. She declined the recommended adjuvant radiation therapy. A follow-up CT of the neck with contrast done a year later revealed a suspicious area of enhancement around the prior resection margin with regional cervical lymphadenopathy. Further workup, including biopsy, confirmed local recurrence. She was treated with definitive cisplatin-based chemoradiotherapy, achieving complete response. She remains without recurrence with more than 24 months of follow-up.

Detection of human papilloma virus subtypes 16 and P16ink4a in invasive squamous cell carcinoma of the fallopian tube and concomitant squamous cell carcinoma in situ of the cervix

Squamous cell carcinoma (SCC) of the fallopian tube is rare and often diagnosed postoperatively. Cervical cancer is considered as a long‐term sequaele, resulting from sexual transmitted infection with certain common high‐risk human papilloma virus (HPV) types. The role of human papilloma virus in the development of the tubal SCC is unknown. We report an unusual case of SCC of the fallopian tube, synchronously occurring with cervical SCC in situ in a 49‐year‐old patient. Histological examination of the entire endometrium revealed no involvement. Both tubal and cervical lesions showed the presence of high risk HPV 16 by PCR and increased expression of p16INK4a protein. Both SCC of the fallopian tube and cervical SCC in situ were positive for p63, while the non‐involved tubal epithelium was positive for WT‐1, but negative for p63. In conclusion, the concomitant occurrence of fallopian tube and cervical SCC can be explained by: (i) the ‘field effect’ of HPV infection resulting in the concomitant development of primary SCC in various sites of the female genital tract; (ii) the primary fallopian tube SSC metastasizing to the uterine cervix; or (iii) primary cervical SCC metastasizing to the fallopian tube. The detection of HPV 16 and p16INK4a in both the fallopian tube and cervical SCCs strengthens the hypothesis of the ‘field effect’ of HPV infection.

Novel intronic germline FLCN gene mutation in a patient with multiple ipsilateral renal neoplasms

Multiple renal tumors of diverse morphology are rare and typically seen in Birt-Hogg-Dubé syndrome. Birt-Hogg-Dubé syndrome is a rare inherited cancer syndrome caused by a germline mutation in the folliculin (FLCN) gene, but the genetic causes for histologic diversity of renal tumors in Birt-Hogg-Dubé syndrome have not been elucidated. We describe here a 64-year-old man with a novel germline mutation in the FLCN gene who presented with 3 phenotypically distinct renal tumors in the same kidney, which were histologically classified as oncocytoma (1.4 cm), oncocytic papillary carcinoma (0.5 cm), and clear cell renal carcinoma (0.8 cm). Genetic analysis of normal kidney tissue revealed a heterozygous germline FLCN mutation (intron 9, IVS9+6 C>T). Additional molecular genetic testing revealed somatic mutations and epigenetic events in genes typically associated with these specific histologic tumor types: oncocytoma harbored a second FLCN mutation (intron 12, IVS12+4 C>T), oncocytic papillary carcinoma harbored promoter methylation of FLCN, and a missense mutation in the MET gene (P246L), whereas clear cell carcinoma harbored inactivating VHL mutation (5-base pair deletion in exon 2) and VHL gene promoter methylation. In addition, chromosomal analysis of peripheral blood lymphocytes showed low level chromosome instability, not previously associated with germline mutations in the FLCN gene.

Pathology of Black Creek Canal virus infection in juvenile hispid cotton rats (Sigmodon hispidus)

The purpose of this study was to assess the effect of inoculum dose on the pathogenesis of Black Creek Canal virus (BCCV) infection in the hispid cotton rat (Sigmodon hispidus), the principal host of BCCV. No sign of illness was observed in any of the 52 juvenile hispid cotton rats inoculated with 3.1, 1.1, -0.9, or -2.9 log(10) median infectious doses(VeroE6) (ID(50-VeroE6)) of BCCV and euthanized on day 9, 18, 27, or 54 postinoculation (PI). Analysis of virus assay and serological data indicated that inoculum dose could significantly affect the pathogenesis of BCCV infection in juvenile hispid cotton rats. For example, the six animals inoculated with 3.1 or 1.1 log(10) ID(50-VeroE6) and euthanized on day 54 PI were virus positive and antibody positive, whereas the six animals inoculated with -0.9 or -2.9 log(10) ID(50-VeroE6) and euthanized on day 54 PI were virus positive but antibody negative. Microscopic examination of tissues from the animals inoculated with 3.1 or 1.1 log(10) ID(50-VeroE6) revealed diffuse, subacute pneumonitis in the lungs of all the animals euthanized on day 18 PI or thereafter, and indicated that the severity of pneumonitis was dependent upon inoculum dose as well as duration of infection (i.e., amount of time elapsed since inoculation).

Detection of prostate cancer with opto-acoustic tomography

The laser optoacoustic imaging system (LOIS) for prostate cancer detection, localization and characterization with 32-element transducer array was developed and tested. Each transducer was made of 50-μm thick PVDF film with dimensions of 1mm x 10 mm. The thickness of the PVDF film allowed 100-μm axial in-depth resolution. Cylindrical shape of the 5-cm long transducer array provided an improved lateral resolution of 0.35 mm. Original design of low noise preamplifiers and wide band amplifiers was employed. The system was optimized for contrast and sensitivity. An automatic recognition of the opto-acoustic signal detected from the irradiated surface was implemented in order to visualize the prostate surface and improve the accuracy of tumor localization. Radial back-projection algorithm adopting Radon transform was used for image reconstruction. The advantages and limitations various contrast enhancing filters applied to the whole image were studied and discussed. Images were acquired in real time with the rate of one frame per second. The system performance was evaluated initially via acquisition of two-dimensional optoacoustic images of small blood volumes in prostate tissue phantoms. Clinical ex-vivo studies of prostatectomy specimen were also performed and compared with transrectal ultrasound.