Elizabeth A. Montgomery

Expression of Yes-associated protein in common solid tumors

The Hippo signaling pathway is a highly conserved potent regulator of cell growth, division, and apoptosis. Yes-associated protein (YAP), the nuclear effector of the Hippo pathway, is a highly conserved component of this pathway in mammalian systems. In humans, amplification of the chromosome region containing the YAP gene (11q22) has been reported in several tumor types. This study was performed to determine if YAP expression was present in 4 common types of malignant tumors that have the highest lifetime risk of causing cancer death among men and women in the United States. The YAP expression intensity and distribution were evaluated in normal tissues and compared to the most frequently occurring malignant tumors in these tissues (colonic adenocarcinoma, lung adenocarcinoma, ovarian serous cystadenocarcinoma, and ductal carcinoma of the breast). For each tissue, the nuclear and cytoplasmic YAP expression intensity was scored as negative, low, or high. We found focal expression of YAP in the progenitor and reparative cellular compartments of normal tissue. In contrast, there was strong and diffuse nuclear and cytoplasmic YAP expression in colonic adenocarcinoma, lung adenocarcinoma, and ovarian serous cystadenocarcinoma. We concluded that the potent Hippo growth regulatory pathway shows markedly different expression patterns in normal tissues of the colon, lung, and ovary compared to the 3 common malignant tumor types we examined in these tissues. Our findings suggest that activation of the Hippo signaling pathway may occur through YAP as part of cell proliferation in normal tissue homeostasis and also might be a frequently activated oncogenic pathway in 3 common malignant tumor types.

Telomere Length Abnormalities Occur Early in the Initiation of Epithelial Carcinogenesis

Purpose: Telomeres help maintain chromosomal integrity. Dysfunctional telomeres can cause genetic instability in vitro and an increased cancer incidence in telomerase knock out mouse models. We recently reported that telomere shortening was a prevalent alteration in human prostate, pancreas, and breast cancer precursor lesions. In the present study, we address whether the previous findings are broadly applicable to human epithelial cancer precursors in general. Experimental Design: Surgical specimens of epithelial cancer precursor lesions from the urinary bladder, esophagus, large intestine, oral cavity, and uterine cervix were examined using a recently developed technique for direct in situ telomere length assessment in formalin-fixed human tissue specimens. Results: Widespread telomere length abnormalities were nearly universal (97.1% of cases) in the preinvasive stages of human epithelial carcinogenesis in all sites examined in this series, with telomere shortening the predominant abnormality (88.6% of cases). Conclusions: Telomere length abnormalities appear to be one of the earliest and most prevalent genetic alterations acquired in the multistep process of malignant transformation. These findings support a model whereby telomere dysfunction induces chromosomal instability as an initiating event in many, perhaps most, human epithelial cancers. Together with previous findings from the prostate and pancreas, the percentage of intraepithelial neoplasia lesions showing telomere length abnormalities is 95.6%. The implications of these findings include the potential that telomere length assessment in situ may be a widely useful biomarker for monitoring disease prevention strategies and for improved early diagnosis.

Prevalence of the alternative lengthening of telomeres telomere maintenance mechanism in human cancer subtypes

Approximately 10% to 15% of human cancers lack detectable telomerase activity, and a subset of these maintain telomere lengths by the telomerase-independent telomere maintenance mechanism termed alternative lengthening of telomeres (ALT). The ALT phenotype, relatively common in subtypes of sarcomas and astrocytomas, has rarely been reported in epithelial malignancies. However, the prevalence of ALT has not been thoroughly assessed across all cancer types. We therefore comprehensively surveyed the ALT phenotype in a broad range of human cancers. In total, two independent sets comprising 6110 primary tumors from 94 different cancer subtypes, 541 benign neoplasms, and 264 normal tissue samples were assessed by combined telomere-specific fluorescence in situ hybridization and immunofluorescence labeling for PML protein. Overall, ALT was observed in 3.73% (228/6110) of all tumor specimens, but was not observed in benign neoplasms or normal tissues. This is the first report of ALT in carcinomas arising from the bladder, cervix, endometrium, esophagus, gallbladder, kidney, liver, and lung. Additionally, this is the first report of ALT in medulloblastomas, oligodendrogliomas, meningiomas, schwannomas, and pediatric glioblastoma multiformes. Previous studies have shown associations between ALT status and prognosis in some tumor types; thus, further studies are warranted to assess the potential prognostic significance and unique biology of ALT-positive tumors. These findings may have therapeutic consequences, because ALT-positive cancers are predicted to be resistant to anti-telomerase therapies.

Nuclear beta-catenin expression distinguishes deep fibromatosis from other benign and malignant fibroblastic and myofibroblastic lesions.

Deep fibromatoses (desmoid tumors) are clonal myofibroblastic proliferations that are prone to aggressive local recurrences but that do not metastasize. They must be distinguished from a host of fibroblastic and myofibroblastic lesions as well as from smooth muscle neoplasms. Virtually all deep fibromatoses have somatic β-catenin or adenomatous polyposis coli (APC) gene mutations leading to intranuclear accumulation of β-catenin. Since low-grade sarcomas in general lack β-catenin and since reactive proliferations would not be expected to have it, we predicted that nuclear β-catenin expression would be detected in deep fibromatoses but absent in other entities in the differential diagnosis. We evaluated the role of β-catenin to help differentiate distinguish deep fibromatoses from congeners. Formalin-fixed, paraffin-embedded sections from 21 lesions from 20 patients with deep fibromatoses were stained with monoclonal β-catenin antibody (Transduction Laboratories) and compared with low-grade fibromyxoid sarcoma (n = 12), leiomyosarcoma (n = 10), various other fibrosarcoma variants (n = 13, including 3 myofibrosarcomas, 3 sclerosing epithelioid fibrosarcomas, 5 low-grade fibrosarcomas, 1 classic fibrosarcoma arising in dermatofibrosarcoma protuberans, 1 inflammatory myxohyaline tumor/myxoinflammatory fibroblastic sarcoma), myofibroma/myofibromatosis (n = 12), nodular fasciitis (n = 11), and scars (n = 9). Nuclear and cytoplasmic staining was assessed. All 21 examples of deep fibromatosis displayed nuclear β-catenin (focal nuclear staining in one case to 90% staining). All other lesions tested (n = 67) lacked nuclear labeling for β-catenin, showing only cytoplasmic accumulation. β-Catenin immunohistochemistry separates deep fibromatosis from entities in the differential diagnosis, a finding that can be exploited for diagnosis. Most fibromatoses have diffuse nuclear staining although occasional examples only focally label.

Confocal laser endomicroscopy in Barrett's esophagus and endoscopically inapparent Barrett's neoplasia: a prospective, randomized, double-blind, controlled, crossover trial

BACKGROUND The detection of high-grade dysplasia and cancer in Barretts esophagus (BE) can be challenging. Confocal laser endomicroscopy (CLE) allows in vivo visualization of mucosal histology during endoscopy. OBJECTIVE To determine whether CLE with optical biopsy and targeted mucosal biopsy improves the diagnostic yield of endoscopically inapparent, BE-associated neoplasia compared to standard endoscopy with a 4-quadrant, random biopsy protocol. DESIGN Prospective, double-blind, randomized, crossover study. SETTING Single, tertiary-care academic center. PATIENTS This study involved patients with BE undergoing routine surveillance or referred for treatment of nonlocalized, endoscopically inapparent, BE-associated neoplasia. INTERVENTION All participants underwent both a confocal endomicroscopy with a targeted biopsy procedure and standard endoscopy with a 4-quadrant biopsy procedure in a randomized order. MAIN OUTCOME MEASUREMENTS Increase in diagnostic yield for neoplasia, reduction in mucosal biopsy number, final pathologic diagnosis. RESULTS CLE with targeted biopsy almost doubled the diagnostic yield for neoplasia and was equivalent to the standard protocol for the final diagnosis of neoplasia. Two thirds of patients in the surveillance group did not need any mucosal biopsies at all. LIMITATION Single-center study. CONCLUSION CLE with targeted biopsy significantly improves the diagnostic yield for endoscopically inapparent BE neoplasia compared to a standard endoscopy with a random-biopsy protocol. CLE with targeted biopsy also greatly reduces the number of biopsies needed per patient and allows some patients without neoplasia to completely forgo mucosal biopsy.

Inflammatory myofibroblastic tumors of the urinary tract: A clinicopathologic study of 46 cases, including a malignant example Inflammatory fibrosarcoma and a subset associated with high-grade urothelial carcinoma

Inflammatory myofibroblastic tumor (IMT) of the urinary tract, also termed postoperative spindle cell nodule, inflammatory pseudotumor, and pseudosarcomatous fibromyxoid tumor, is rare and in the past was believed to reflect diverse entities. We reviewed a series of 46 IMTs arising in the ureter, bladder, and prostate, derived primarily from a large consultation practice. There were 30 male and 16 females aged 3 to 89 years (mean 53.6). Lesions were 1.2 to 12 cm (mean 4.2). There was a history of recent prior instrumentation in 8 cases. Morphology was similar to that previously described for IMT occurring in this region, with the exception of 1 case that focally appeared sarcomatous. Polypoid cystitis coexisted in 5 patients (11%). Mitoses were typically scant (0 to 20/10 hpf, mean 1). Necrosis was seen in 14 (30%) cases. Invasion of the muscularis propria was documented in 19 (41%). By immunohistochemistry (IHC), lesions at least focally expressed anaplastic lymphoma kinase (ALK) (20/35, 57%), AE1/3 (25/34, 73%), CAM5.2 (10/15, 67%), CK18 (6/6, 100%), actin (23/25, 92%), desmin (15/19, 79%), calponin (6/7, 86%), caldesmon (4/7, 57%, rare cells), p53 (10/13, 77%), and most lacked S100 (0/14), CD34 (0/13), CD117 (2/13, 15%), CD21 (0/5), and CD23 (0/3). ALK gene alterations were detected by fluorescence in situ hybridization (FISH) in 13/18 (72%) tested cases, including 2 with prior instrumentation; 13/18 (72%) showed agreement between FISH ALK results and ALK protein results by IHC. Most bladder IMTs were managed locally, but partial cystectomy was performed as the initial management in 7 cases and cystectomy in 1 (1 IMT was initially misinterpreted as carcinoma, 1 IMT was found incidentally as a separate lesion in a cystectomy specimen performed for urothelial carcinoma). Follow-up was available in 32 cases (range 3 to 120 mo; mean 33; median 24). There were 10 patients with recurrences (2 with 2 recurrences). Recurrences were unassociated with muscle invasion or with ALK alterations. In 2 cases, tumors of the urinary tract (TURs) showing IMT preceded (1 and 2 mo, respectively) TURs showing sarcomatoid carcinoma with high-grade invasive urothelial carcinoma accompanied with separate fragments of IMT. Even on re-review the IMT in these 2 cases were morphologically indistinguishable from other cases of IMT, with FISH demonstrating ALK alterations in the IMT areas in one of them. Both these patients died of their carcinomas. Lastly, there was 1 tumor with many morphological features of IMT and an ALK rearrangement, yet overtly sarcomatous. This case arose postirradiation for prostate cancer 4 years before the development of the lesion, with tumor recurrence at 4 months and death from intra-abdominal metastatic disease at 9 months. In summary, urinary tract IMTs are rare and share many features with counterparts in other sites, displaying similar morphology and immunogenotypic features whether de novo or postinstrumentation. Typical IMTs can be locally aggressive, sometimes requiring radical surgical resection, but none of our typical cases metastasized, although they can rarely arise contemporaneously with sarcomatoid urothelial carcinomas. For these reasons, close follow-up is warranted.

Aberrant Epithelial–Mesenchymal Hedgehog Signaling Characterizes Barrett's Metaplasia

BACKGROUND & AIMS The molecular mechanism underlying epithelial metaplasia in Barretts esophagus remains unknown. Recognizing that Hedgehog signaling is required for early esophageal development, we sought to determine if the Hedgehog pathway is reactivated in Barretts esophagus, and if genes downstream of the pathway could promote columnar differentiation of esophageal epithelium. METHODS Immunohistochemistry, immunofluorescence, and quantitative real-time polymerase chain reaction were used to analyze clinical specimens, human esophageal cell lines, and mouse esophagi. Human esophageal squamous epithelial (HET-1A) and adenocarcinoma (OE33) cells were subjected to acid treatment and used in transfection experiments. Swiss Webster mice were used in a surgical model of bile reflux injury. An in vivo transplant culture system was created using esophageal epithelium from Sonic hedgehog transgenic mice. RESULTS Marked up-regulation of Hedgehog ligand expression, which can be induced by acid or bile exposure, occurs frequently in Barretts epithelium and is associated with stromal expression of the Hedgehog target genes PTCH1 and BMP4. BMP4 signaling induces expression of SOX9, an intestinal crypt transcription factor, which is highly expressed in Barretts epithelium. We further show that expression of Deleted in Malignant Brain Tumors 1, the human homologue of the columnar cell factor Hensin, occurs in Barretts epithelium and is induced by SOX9. Finally, transgenic expression of Sonic hedgehog in mouse esophageal epithelium induces expression of stromal Bmp4, epithelial Sox9, and columnar cytokeratins. CONCLUSIONS Epithelial Hedgehog ligand expression may contribute to the initiation of Barretts esophagus through induction of stromal BMP4, which triggers reprogramming of esophageal epithelium in favor of a columnar phenotype.

Frequent β-Catenin Mutations in Juvenile Nasopharyngeal Angiofibromas

Juvenile nasopharyngeal angiofibromas (JNAs) are locally aggressive vascular tumors occurring predominantly in adolescent males. The pathogenesis of JNAs is unknown. Recently, JNAs have been reported to occur at increased frequency among patients with familial adenomatous polyposis, suggesting that alterations of the adenomatous polyposis coli (APC)/β-catenin pathway might also be involved in the pathogenesis of sporadic JNAs. We analyzed somatic β-catenin and APC gene mutations in 16 sporadic JNAs from nonfamilial adenomatous polyposis patients using immunohistochemistry for β-catenin, and direct DNA sequencing for exon 3 of the β-catenin gene and the mutation cluster region of the APC gene. Nuclear accumulation of β-catenin was diffusely present in the stromal cells but not in the endothelial cells of all 16 JNAs. Activating β-catenin gene mutations were present in 75% (12 of 16) of JNAs. Six JNA patients also had recurrent tumors after surgery, and in all cases the β-catenin gene status of the recurrent JNA was identical to the initial tumor. No mutations in the mutation cluster region of the APC gene were detected in the four JNAs without β-catenin mutations. The high frequency of β-catenin mutations in sporadic JNAs and the presence of identical β-catenin gene mutations in recurrent tumors indicates that activating β-catenin gene mutations are important in the pathogenesis of JNAs. The immunohistochemical localization of β-catenin only to the nuclei of stromal cells further suggests that the stromal cells, rather than endothelial cells, are the neoplastic cells of JNAs.

Pleomorphic liposarcoma: A clinicopathologic analysis of 19 cases

Pleomorphic liposarcoma is a variant of liposarcoma defined morphologically by the presence of pleomorphic lipoblasts. Because of its rarity, there are limited studies with long-term follow-up information. Nineteen pleomorphic liposarcomas were studied. Unequivocal pleomorphic lipoblasts were required for inclusion. In each case, the following features were noted: tumor site; tumor size; tumor depth; predominant histologic pattern (epithelioid or malignant fibrous histiocytoma [MFH]-like); extent of necrosis (absent, less than 15%, or at least 15%); mitotic counts; treatment and clinical follow-up. Patients were 11 females and 8 males, aged 33–87 years (mean, 64.5 y; median, 70 y). Tumors involved the extremities (13 patients: intramuscular in 10, subcutaneous in 2, depth unknown in 1), retroperitoneum (4 patients), mediastinum (1 patient), and paratesticular region (1 patient). Size ranged from 4.5–31 cm (mean, 11.9 cm; median, 12.0 cm). Predominant pattern was epithelioid in 7 and MFH-like in 12. Necrosis was present in 15 (79%) and was extensive (36 15%) in 14 patients. Mitotic counts ranged from 0.2–3.4/10 high-power fields (mean, 1.4; median, 1.4) by the average-count method and from 1–6/10 high power fields by the highest count method (mean, 2.9; median, 3.0). All patients were treated surgically; 10 patients received adjuvant chemotherapy and/or radiation therapy. On follow-up of 18 patients (range, 2–129 mo; mean, 35.4 mo; median, 23 mo) nine (50%) were dead of disease (range, 2–48 mo; mean, 20.1 mo; median, 12 mo), one died of other causes 2 months after diagnosis, two were alive with disease, five were disease free, and one was alive at 129 months (tumor status unknown). Five had recurrences (range, 3–28 mo; mean, 14.4 mo; median, 8 mo), and four of five (80%) with recurrences were dead of disease. Metastases developed in eight patients (range, 4–48 mo; mean, 19.5 mo; median, 11.5 mo), most commonly to the lungs. In conclusion, pleomorphic liposarcoma is a rare tumor of adulthood that occurs most commonly in the deep, soft tissues of the extremities. It behaves as a high-grade sarcoma that frequently metastasizes, most commonly to the lungs. Although this tumor has a wide range of histologic appearances, no clinical or pathologic feature is predictive of a more aggressive clinical course.

Counting alleles reveals a connection between chromosome 18q loss and vascular invasion.

The analysis of loss of heterozygosity (LOH) is perhaps the most widely used technique in cancer genetics. In primary tumors, however, the analysis of LOH is fraught with technical problems that have limited its reproducibility and interpretation. In particular, tumors are mixtures of neoplastic and nonneoplastic cells, and the DNA from the nonneoplastic cells can mask LOH. We here describe a new experimental approach, involving two components, to overcome these problems. First, a form of digital PCR was employed to directly count, one by one, the number of each of the two alleles in tumor samples. Second, Bayesian-type likelihood methods were used to measure the strength of the evidence for the allele distribution being different from normal. This approach imparts a rigorous statistical basis to LOH analyses, and should be able to provide more reliable information than heretofore possible in LOH studies of diverse tumor types.