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Dive into the research topics where David G. Allen is active.

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Featured researches published by David G. Allen.


British Journal of Cancer | 2000

Progressive genetic aberrations detected by comparative genomic hybridization in squamous cell cervical cancer

David G. Allen; D. J. White; A. M. Hutchins; James Scurry; S. N. Tabrizi; Suzanne M. Garland; J. E. Armes

Genetic changes orchestrated by human papillomaviruses are the most important known factors in carcinogenesis of the uterine cervix. However, it is clear that additional genetic events are necessary for tumour progression. We have used comparative genomic hybridization to document non-random chromosomal gains and losses within a subset of 37 cervical carcinomas matched for clinical stage Ib, but with different lymph node status. There were significantly more chromosomal changes in the primary tumours when the lymph nodes were positive for metastases. The most frequent copy number alterations were loss of 3p, 11q, 6q and 10q and gain of 3q. The smallest areas of loss and gain on chromosome 3 were 3p14–22 and 3q24–26. The study identifies progressive DNA copy number changes associated with early-stage invasive cervical cancers with and without lymph node metastases, a factor of potential prognostic and therapeutic value.


Pathology | 2008

Diagnostic utility of p16INK4a: a reappraisal of its use in cervical biopsies

Nicholas J. Mulvany; David G. Allen; Sharyn M. Wilson

&NA; p16INK4a, an indirect marker of cell cycle dysregulation, is commonly expressed in cervical dysplasias and carcinomas associated with high risk human papillomavirus (HR‐HPV) infections. Although p16INK4a immunohistology is routinely used as a cost effective surrogate marker, many of the published articles are confusing and contradictory. The discrepancies can be ascribed to a multitude of factors operating at the molecular, technical and interpretative levels. In the first place, our simplistic model of viral mediated oncogenesis is speculative and fails to account for all the known biomolecular changes. Unresolved technical issues include the variables of tissue fixation, antibody dilution, antibody isotype and clone, and the sensitivity of the particular detection method. Within any controlled staining method, strong diffuse or ‘block’ immunoreactivity in squamous cells may be found in moderate/severe dysplasia (CIN 2/3) and invasive squamous carcinoma. In contrast, focal or multifocal reactivity in squamous cells may be artefactual, related to low risk or HR‐HPV. p16INK4a is less reliable when dealing with glandular lesions since considerable overlap exists between reactive and dysplastic lesions. In addition not all glandular dysplasias/carcinomas are HR‐HPV related, nor are all p16INK4a immunoreactive lesions associated with HR‐HPV. We conclude that p16INK4a immunoperoxidase shows greater specificity than sensitivity for squamous lesions; in comparison, glandular dysplasias/carcinomas show reduced specificity and sensitivity. Like all cell cycle regulatory proteins, the future diagnostic role of p16INK4a is limited. The ideal diagnostic molecular test for cervical dysplasias will detect a HR‐HPV related product after, but not before, cell transformation and will reliably predict those cases yet to experience disease progression.


International Journal of Gynecological Pathology | 2008

Differentiated Intraepithelial Neoplasia of the Vulva

Nicholas J. Mulvany; David G. Allen

Summary We present the clinical and pathological findings of 6 women with intraepithelial neoplasia of differentiated or simplex type (DVIN). The mean age was 68 years (range 55-82). One lesion was still in situ, whereas 5 were associated with squamous carcinoma, 4 of well-differentiated keratinizing type and 1 of poorly differentiated spindle-cell type. The invasive depth of the squamous carcinomas ranged from 0.6 to 8 mm and the surgical margins of all of the resection specimens were uninvolved by neoplastic cells. In contrast, DVIN involved the surgical margins in 5 specimens while the remaining specimen had normal surgical margins. In all 6 vulvar specimens, DVIN showed intense immunoreactivity for Ki-67 in the basal and parabasal cells while only 4 specimens showed reactivity for p53. In 5 surgical specimens with DVIN the number of CD1a cells was increased but little if any immunoreactivity could be found amongst the corresponding invasive neoplastic cells. Four squamous carcinomas also showed diffuse p53 reactivity. There was little difference in the pattern of Ki-67 expression between DVIN and squamous carcinoma. For a number of reasons, DVIN present diagnostic difficulty and considerable interobserver variation also exists. Our study suggests that Ki-67 and p16INK4A are useful for distinguishing DVIN and classical VIN 3, whereas p53 and CD1a are useful for distinguishing DVIN and invasive squamous carcinoma. Furthermore, p53 appears to have higher specificity than sensitivity for distinguishing DVIN from normal squamous epithelium.


International Journal of Gynecological Pathology | 2005

Abnormalities of the RB1 pathway in ovarian serous papillary carcinoma as determined by overexpression of the p16(INK4A) protein.

Jane E. Armes; Rohan Lourie; Melanie de Silva; Georgia Stamaratis; Alison Boyd; Beena Kumar; Gareth Price; Simon Hyde; David G. Allen; Peter Grant; Deon J. Venter

Summary:Dysfunction of proteins involved in the G1 to S transition of the cell cycle, such as p16(INK4A) and RB1, is common in many cancer types. A screen of p16 protein expression was performed in benign, borderline, and invasive ovarian tumors, together with endometrial cancers, aligned on a tissue microarray. We observed frequent p16 overexpression in serous papillary carcinomas of ovarian and endometrial origin. An extended cohort of ovarian serous papillary carcinomas was examined to further evaluate the frequency of p16 overexpression. Strong, uniform staining in the majority of cancer cells occurred commonly in invasive serous papillary ovarian cancers, particularly in grade 3 carcinomas. RB1 protein expression abnormalities were rare. Our data indicate that abnormalities in the retinoblastoma pathway, as determined by p16 overexpression, are common in serous papillary carcinomas and are probably an early event.


British Journal of Cancer | 2002

Genetic aberrations detected by comparative genomic hybridisation in vulvar cancers

David G. Allen; Anne-Marie Hutchins; Fleur Hammet; White Dj; James Scurry; Sepehr N. Tabrizi; Suzanne M. Garland; Jane E. Armes

Squamous cell carcinoma of the vulva is a disease of significant clinical importance, which arises in the presence or absence of human papillomavirus. We used comparative genomic hybridisation to document non-random chromosomal gains and losses within human papillomavirus positive and negative vulvar cancers. Gain of 3q was significantly more common in human papillomavirus-positive cancers compared to human papillomavirus-negative cancers. The smallest area of gain was 3q22–25, a chromosome region which is frequently gained in other human papillomavirus-related cancers. Chromosome 8q was more commonly gained in human papillomavirus-negative compared to human papillomavirus-positive cancers. 8q21 was the smallest region of gain, which has been identified in other, non-human papillomavirus-related cancers. Chromosome arms 3p and 11q were lost in both categories of vulvar cancer. This study has demonstrated chromosome locations important in the development of vulvar squamous cell carcinoma. Additionally, taken together with previous studies of human papillomavirus-positive cancers of other anogenital sites, the data indicate that one or more oncogenes important in the development and progression of human papillomavirus-induced carcinomas are located on 3q. The different genetic changes seen in human papillomavirus-positive and negative vulvar squamous cell carcinomas support the clinicopathological data indicating that these are different cancer types.


International Journal of Gynecological Pathology | 2008

Combined large cell neuroendocrine and endometrioid carcinoma of the endometrium.

Nicholas J. Mulvany; David G. Allen

Summary We present the surgical and pathological findings and follow-up of 5 women diagnosed with combined endometrioid and high-grade neuroendocrine carcinoma of large cell type (LCNEC) arising in the endometrium. The mean age of the women was 75 years (range, 50-88 years). Of the 5 tumors, 4 formed polypoid endometrial masses associated with extensive lymphovascular involvement of the myometrium by neoplastic cells. A single endometrial tumor was formed by LCNEC alone, and 4 tumors were composite with varying proportions formed by endometrioid (4/5) and small cell neuroendocrine carcinoma (1/5). In all 5 LCNEC tumor components, an insular growth pattern was noted, whereas a diffuse (solid) pattern was found in 4 tumors, a trabecular in 2, and rosettes/pseudorosettes in another 2. In all 5 tumors, the LCNEC tumor components were labeled with neuron-specific enolase (NSE). Four tumors were reactive for chromogranin A, CAM 5.2, and p53. Three tumors were labeled for AE1/AE3, CD56 (NCAM), p16INK4A, and cytokeratin 7. Synaptophysin was reactive in 2 tumors, and CD117 was found in only a single tumor. Of the 3 endometrioid tumor components examined, all were reactive for NSE. Two tumors were reactive for p16INK4A and p53, 1 for CD56, but none for synaptophysin orchromogranin A. We conclude that LCNEC of the endometrium is a distinct clinicopathological entity with a poor prognosis irrespective of stage. The gross and histomorphological features are often suggestive, but confirmation requires immunoperoxidases, including NSE, synaptophysin, chromogranin A, p16INK4A, and p53. Combined endometrioid and high-grade LCNEC possess more characteristics of a type II than a type I endometrial carcinoma.


International Journal of Gynecological Pathology | 2003

Pseudoepitheliomatous hyperplasia in lichen sclerosus of the vulva.

Eung Seok Lee; David G. Allen; James Scurry

Small tentacles or separated nests of squamous cells in the dermis are not uncommonly seen in long-standing vulvar lichen sclerosus (LS) associated with epidermal thickening. We recently encountered a case where separated nests of well-differentiated squamous cells in the dermis were difficult to distinguish from squamous cell carcinoma (SCC). Further biopsies showed similar nests originating from every hair follicle. We postulated a diagnosis of multifocal pseudoepitheliomatous hyperplasia (PEH) to explain this phenomenon. Because we could find no reference to PEH in the setting of LS, we reviewed the biopsies of 92 women with extragenital and vulvar LS with and without carcinoma to determine its frequency and histological appearance. The study population, which excluded the index case, comprised 10 women with extra-anogenital LS, 58 with vulvar LS without carcinoma, and 24 with vulvar LS with carcinoma. The presence of PEH, epidermal thickness, predominant dermal collagen change, degree of inflammation, and presence of fibrin and red blood cells were recorded. The presence or absence of lichen simplex chronicus (LSC), squamous cell hyperplasia (SCH), and differentiated vulvar intraepithelial neoplasia (VIN) were recorded. PEH was identified only in vulvar LS, where it was seen in 7/58 (12.1%) women without carcinoma, 1/24 (8.3%) with carcinoma, and 0/10 (0%) with extra-anogenital LS. Two forms of PEH were seen: predominantly epidermal 7/8 (87.5%) and predominantly follicular 1/8 (12.5%). PEH was associated with increased epidermal thickness, less dermal edema, more dermal inflammation, fresh fibrin, and red blood cell extravasation. In all cases, there was associated LSC, but there was no SCH or differentiated VIN. In conclusion, PEH may explain many of the cases of dermal tentacles and separated squamous nests in vulvar LS with LSC. The association with fresh fibrin and red blood cells suggests that PEH might be a reaction to tissue damage. PEH is distinguished from SCC by its lack of atypia, confinement to the abnormal collagen, and limited growth. The pathologist must be careful about making a diagnosis of PEH in LS with epidermal thickening, looking carefully for basal atypia and other features of differentiated VIN in the overlying epidermis or dermal proliferation. We do not know whether PEH occurs in differentiated VIN and, if it does, how it could be distinguished from SCC.


Pathology | 2009

Adenocarcinoma cells in Pap smears

Nicholas J. Mulvany; Gerardine Mitchell; David G. Allen

&NA; Adenocarcinomas of the cervix, endometrium, fallopian tube and ovary may present with malignant cells in a Pap smear. In contrast, carcinomas arising outside the female genital tract only rarely present in Pap smears and signs and symptoms of disseminated malignancy are usually evident. Rare isolated metastases to the uterus have been reported and a high index of suspicion is required in such instances. The cell arrangement, pattern of cell spread and the smear background reflect the pathway by which the malignant cells involve the cervix. Recognition of any specific diagnostic features coupled with judicious use of ancillary tests can be of inestimable value. Adequate clinical information, review of past medical history and all previous smears and biopsies form an integral part of the investigation. Consideration of all of these points in conjunction with an appreciation of the classical cytomorphology of endometrioid, serous and clear cell carcinomas should allow a correct diagnosis of extrauterine adenocarcinoma with a high degree of probability.


Internal Medicine Journal | 2011

Intraperitoneal distribution imaging in ovarian cancer patients

Sarah-Jane Dawson; Rodney J. Hicks; Val Johnston; David G. Allen; T. Jobling; Michael A. Quinn; Danny Rischin

Background/Aims: Optimal delivery of intraperitoneal (IP) chemotherapy is dependent on adequate drug distribution. An accurate understanding of the limitations of IP distribution is critical if we are to improve cytotoxic delivery through this route.


Journal of Medical Imaging and Radiation Oncology | 2009

Prognostic significance of several histological features in intermediate and high-risk endometrial cancer patients treated with curative intent using surgery and adjuvant radiotherapy

Kailash Narayan; Rejeki; Alan Herschtal; David Bernshaw; Michael Quinn; Tom Jobling; David G. Allen

The purpose of the present study was to explore the prognostic significance of several histological features with respect to lymph node metastasis, failure‐free survival (FFS), and overall survival (OS) in intermediate and high‐risk endometrial cancer patients treated with curative intent. One hundred and eighty patients with endometrial cancer were treated with hysterectomy with or without lymphadenectomy and received external beam radiotherapy (EBRT). The mean follow‐up period was 4.25 years (range 0.44–10.45 years). In multifactor analysis, fractional myometrial invasion (MI) (P = 0.047), histology (P < 0.001) and lymph‐vascular space invasion (LVSI) (P = 0.025) were significant predictors for FFS when nodal status was not included. When lymph node status was known, histology (P = 0.007) and LVSI (P = 0.014) remained significant factors for FFS. For OS, histology (P < 0.001) and fractional MI (P = 0.004) were the significant factors. Lymph node status could be predicted by tumour grading (P = 0.016) and absolute MI (P = 0.002). Histology type and the presence of LVSI were the most important prognostic factors in high‐risk endometrial cancer patients treated by surgery and postoperative radiotherapy. Absolute MI and tumour grading were useful predictors of nodal spread.

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Peter Grant

Mercy Hospital for Women

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James Scurry

University of Newcastle

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Simon Hyde

Mercy Hospital for Women

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Ruud L.M. Bekkers

Radboud University Nijmegen

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Danny Rischin

Peter MacCallum Cancer Centre

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Kailash Narayan

Peter MacCallum Cancer Centre

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