Potential genetic anticipation in hereditary leiomyomatosis-renal cell cancer (HLRCC).

Hereditary leiomyomatosis-renal cell cancer (HLRCC) is an autosomal dominant disorder characterised by cutaneous leiomyomas, symptomatic uterine leiomyomas and aggressive type II papillary renal cell carcinoma. It is caused by heterozygous mutations in the fumarate hydratase (FH) gene on chromosome 1q43. We present evidence of genetic anticipation in HLRCC syndrome. A comprehensive literature review was performed to determine the potential for genetic anticipation in HLRCC syndrome. The normal random effects model was used to evaluate for genetic anticipation to ensure reduction in bias. A total of 11 FH kindreds with available multi-generational data were identified for analysis. The mean difference in age at diagnosis of RCC between the first and second generation was -18.6 years (95 % CI -26.6 to -10.6, p < 0.001). The mean difference in age at diagnosis of RCC between the first and third generation was -36.2 years (95 % CI -47.0 to -25.4, p < 0.001). No evidence of anticipation for uterine leiomyomas was observed (p = 0.349). We report preliminary evidence of genetic anticipation of RCC in HLRCC syndrome. Additional clinical validation is important to confirm this observation, which may have practical implications on counseling and timing of surveillance initiation. Exploration of the underlying mechanisms of anticipation in HLRCC would be of considerable biological interest.

2011 Young Surgeon's Award Winner: high endothelial venules: a novel prognostic marker in cancer metastasis and the missing link?

INTRODUCTION: The extent of lymph nodes (LNs) metastasis is a major determinant for the staging and the most reliable adverse prognostic factor. Primary tumours can induce lymphatics and vasculature reorganisations within sentinel LN before the arrival of cancer cells and these key blood vessels are identified as high endothelial venules (HEV). The alterations of HEV in the presence of cancer, coupled with the increased proliferation rate of the endothelial cells, results in a functional shift of HEV from immune response mediator to blood flow carrier. We aim to evaluate tumour-induced vascularisation in regional LN of cancer patients by studying the morphological and functional alterations of HEV and its correlation to clinico-pathological features. MATERIALS AND METHODS: This multi-centre study with a prospective database identified 65 consecutive patients with tongue squamous cell carcinoma (SCC) who underwent primary surgical treatment from 2001 to 2005. Immunohistochemical staining for HEV and image analysis were performed and analysed with correlation to the patients' clinico-pathological features. RESULTS: The total number of HEV is significantly associated to disease-free interval when controlling for the group (P = 0.022) as well as combining both groups as one cohort (P = 0.023). There is also a similar association comparing the HEV parameters to overall survival. CONCLUSION: Our results suggest that HEV possibly plays a key role in the pathogenesis of lymphatic and subsequent distant metastases and may provide the missing link in cancer metastasis. Confirmation of this hypothesis would offer a novel therapeutic approach to preventing metastasis by blocking the remodeling processes of HEV in LN.

Keratin 15, transcobalamin I and homeobox gene Hox-B13 expression in breast phyllodes tumors: novel markers in biological classification.

Breast phyllodes tumors are rare neoplasms which present challenges for histological classification. Microscopic features are not always predictive of clinical behavior, and scarce data exist on the prognostic role of biological markers. Our study evaluated a series of 145 phyllodes tumors diagnosed at the Department of Pathology, Singapore General Hospital between 2006 and 2009, incorporating 91 (62.8%) benign, 40 (27.6%) borderline, and 14 (9.7%) malignant phyllodes tumors. Antibodies to keratin 15 (KRT15), transcobalamin I (TCN1), and homeobox gene Hox-B13 (HOXB13) were applied to sections cut from tissue microarray blocks. KRT15 and TCN1 positivity was defined when there was reactivity of 1% or more stromal cells, while HOXB13 positivity was defined using a H-score of 100 and above. Positive immunohistochemical expression for KRT15, TCN1, and HOXB13 was seen in 21 (14.5%), 96 (66.2%), and 66 (45.5%) of tumors, respectively. Stromal expression of KRT15, TCN1, and HOXB13 was significantly correlated with tumor grade (P < 0.001, P < 0.001, P = 0.012), stromal hypercellularity (P = 0.005, P < 0.001, P = 0.023), mitotic activity (P < 0.001), and microscopic borders (P = 0.006, P < 0.001, P = 0.011). Co-expression of TCN1 and HOXB13 was seen in 21 of 91 (23.1%) benign, 18 of 40 (45.0%) borderline, and 11 of 14 (78.6%) malignant tumors, suggesting that the dual-marker panels of TCN1 and HOXB13 might be helpful in classifying borderline and malignant tumors. Although expression of TCN1 alone was present in all malignant and 34 of 40 (85.0%) borderline tumors, a combined panel with HOXB13 excluded some benign cases and was a better discriminant for a significant proportion of borderline and malignant tumors.

Molecular classification of breast phyllodes tumors: validation of the histologic grading scheme and insights into malignant progression.

Phyllodes tumors of the breast are rare fibroepithelial neoplasms with a potential for recurrence. Current histological classification is not always predictive of clinical behavior. The aim of this study was to identify genetic changes associated with the development of borderline and malignant phyllodes tumors in an Asian population, and to assess if genetic data supported the categorization of these tumors into the existing three grades of benign, borderline, and malignant. Expression profiling of 21 phyllodes tumors (6 benign, 10 borderline, 5 malignant) was performed using Affymetrix U133Plus 2.0 GeneChips(®). Gene expression among benign, borderline, and malignant tumors was compared and a 29 gene list was able to classify them according to their histologic grade. Among these 29 genes are those responsible for matrix formation, cell adhesion, epidermis formation, and cell proliferation. Comparative genomic microarray analysis showed that the most common chromosomal alteration associated with borderline and malignant tumors was 1q gain, and an increasing number of chromosomal changes was noted with increasing histological grade. Upregulation of HOXB13 was seen in malignant relative to borderline phyllodes tumors and further investigated by immunohistochemistry in a corresponding set of formalin-fixed, paraffin-embedded tumors. HOXB13 protein overexpression was found to be correlated with stromal hypercellularity and atypia (P = 0.03, P = 0.039, respectively) and may be implicated in the development of malignant phyllodes tumors.

A unique pair of monozygotic twins with concordant clear cell renal cell carcinoma: a case report.

INTRODUCTION: Genetic predisposition to clear cell renal cell carcinoma (ccRCC) has been linked to disorders such as von Hippel-Lindau (VHL) syndrome. While twin research is a classic approach for elucidating genetic and environmental contributions to disease, no monozygotic twin-pair concordant for ccRCC in the absence of VHL syndrome has been previously reported in the literature or in major twin registries. CLINICAL PICTURE: We describe a unique monozygotic twin-pair concordant for ccRCC, with discordant but early ages of onset of 25 and 38 respectively. Cytogenetic studies and direct sequencing for VHL gene mutations in the second twin proved unremarkable. CONCLUSIONS: This is the fi rst reported case of monozygotic twins concordant for ccRCC in the absence of VHL gene mutation. The early yet discordant, age of onset of disease in both twins suggests both genetic and environmental contributions to ccRCC.

Virus-specific read-through codon preference affects infectivity of chimeric cucumber green mottle mosaic viruses displaying a dengue virus epitope.

A Cucumber green mottle mosaic virus (CGMMV) was used to present a truncated dengue virus type 2 envelope (E) protein binding region from amino acids 379 to 423 (EB4). The EB4 gene was inserted at the terminal end of the CGMMV coat protein (CP) open reading frame (ORF). Read-through sequences of TMV or CGMMV, CAA-UAG-CAA-UUA, or AAA-UAG-CAA-UUA were, respectively, inserted in between the CP and the EB4 genes. The chimeric clones, pRT, pRG, and pCG+FSRTRE, were transcribed into full-length capped recombinant CGMMV transcripts. Only constructs with the wild-type CGMMV read-through sequence yielded infectious viruses following infection of host plant, muskmelon (Cucumis melo) leaves. The ratio of modified to unmodified CP for the read-through expression clone developed was also found to be approximately 1:1, higher than what has been previously reported. It was also observed that infectivity was not affected by differences in pI between the chimera and its wild counterpart. Analysis of recombinant viruses after 21-days-postinculation (dpi) revealed that deletions occurred resulting in partial reversions of the viral population to near wild type and suggesting that this would be the limiting harvest period for obtaining true to type recombinants with this construct.