Induction and preliminary characterization of neoplastic pulmonary nodules in a transgenic pig model

OBJECTIVES

Lung cancer models in large animals are lacking. Oncopigs are transgenic pigs that carry both KRASG12D and TP53R167H Cre-inducible mutations. This study aimed to develop and histologically characterize a swine model of lung cancer that could serve for preclinical studies evaluating locoregional therapies.

MATERIALS AND METHODS

In two Oncopigs, an adenoviral vector encoding the Cre-recombinase gene (AdCre) was injected endovascularly through the pulmonary arteries or inferior vena cava. In two other Oncopigs, a lung biopsy was performed and incubated with AdCre, before reinjecting the mixture into the lungs percutaneously. Animals were clinically and biologically (complete blood count, liver enzymes and lipasemia) monitored. Obtained tumors were characterized on computed tomography (CT) and on pathology and immunohistochemistry (IHC).

RESULTS

Neoplastic lung nodules developed following 1 (1/10, 10%) endovascular inoculation, and 2 (2/6, 33%) percutaneous inoculations. All lung tumors were visible at the 1-week CT, and appeared as well-circumscribed solid nodules, with a median longest diameter of 14 mm (range: 5-27 mm). Only one complication occurred: an extravasation of the mixture into the thoracic wall during a percutaneous injection that resulted in a thoracic wall tumor. Pigs remained clinically healthy during the entire follow-up (14-21 days). On histology, tumors consisted of inflammatory undifferentiated neoplasms composed of atypical spindle and epithelioid cells and/or a fibrovascular stroma and abundant mixed leukocytic infiltrate. On IHC, atypical cells diffusely displayed expression of vimentin and some showed expression of CK WSS and CK 8/18. The tumor microenvironment contained abundant IBA1 + macrophages and giant cells, CD3 + T cells, and CD31 + blood vessels.

CONCLUSION

Tumors induced in the lungs of Oncopigs are fast growing poorly differentiated neoplasms associated with a marked inflammatory reaction that can be easily and safely induced at site specific locations. This large animal model might be suitable for interventional and surgical therapies of lung cancer.

It takes a village: microbiota, parainflammation, paligenosis and bystander effects in colorectal cancer initiation

Sporadic colorectal cancer (CRC) is a leading cause of worldwide cancer mortality. It arises from a complex milieu of host and environmental factors, including genetic and epigenetic changes in colon epithelial cells that undergo mutation, selection, clonal expansion, and transformation. The gut microbiota has recently gained increasing recognition as an additional important factor contributing to CRC. Several gut bacteria are known to initiate CRC in animal models and have been associated with human CRC. In this Review, we discuss the factors that contribute to CRC and the role of the gut microbiota, focusing on a recently described mechanism for cancer initiation, the so-called microbiota-induced bystander effect (MIBE). In this cancer mechanism, microbiota-driven parainflammation is believed to act as a source of endogenous mutation, epigenetic change and induced pluripotency, leading to the cancerous transformation of colon epithelial cells. This theory links the gut microbiota to key risk factors and common histologic features of sporadic CRC. MIBE is analogous to the well-characterized radiation-induced bystander effect. Both phenomena drive DNA damage, chromosomal instability, stress response signaling, altered gene expression, epigenetic modification and cellular proliferation in bystander cells. Myeloid-derived cells are important effectors in both phenomena. A better understanding of the interactions between the gut microbiota and mucosal immune effector cells that generate bystander effects can potentially identify triggers for parainflammation, and gain new insights into CRC prevention.

[Colorectal tumor evolution in inflammatory bowel disease : Dynamics of genomic alterations and potential molecular markers to predict malignant progression]

Inflammatory bowel diseases (IBDs) increase the risk for colorectal cancer (CRC). In IBD, the evolution of potential tumor clones occurs long before neoplastic lesions become evident and these clones can be undetectable by endoscopy and histology at early stages. The spectrum of genomic alterations in IBD-associated colorectal carcinogenesis is distinct from the changes observed in the sporadic adenoma-carcinoma sequence. Predominant alterations include aneuploidies and mutations of TP53, which both occur early in IBD-related tumorigenesis. In some IBD patients, genomic alterations can already be detected in colonic mucosa without any histologic signs of dysplasia. Genomic analysis of multiregional samples from colectomy specimens of IBD patients revealed distinct tumor evolutionary patterns. This suggests an increased genomic instability in the chronically inflamed bowel that enables the emergence of multiple, phylogenetically unrelated neoplastic lesions within the colorectum of a single IBD patient. This article summarizes the genomic alterations underlying IBD-associated colorectal tumorigenesis and the evolutionary patterns from inflamed, not yet dysplastic epithelium to CRC. Furthermore, it is discussed how this knowledge can eventually be exploited for early detection of malignant progression of IBD and thus help to improve the clinical management and surveillance schedule of IBD patients.

Clinicopathologic characteristics of ovarian clear cell carcinoma in the background of endometrioma: a surveillance strategy for an early detection of malignant transformation in patients with asymptomatic endometrioma

Objective

This study aimed to analyze the clinical features of clear cell carcinoma in relation to endometriosis and to determine an appropriate surveillance strategy for the early detection of malignant transformation of endometrioma in asymptomatic patients.

Methods

We retrospectively reviewed the clinicopathologic data of 50 patients with ovarian clear cell carcinoma. Clinicopathologic characteristics, treatment outcomes, and the association between endometriosis and the risk of malignant transformation were analyzed.

Results

Ten (20%) patients had been diagnosed with endometrioma before the diagnosis of clear cell carcinoma. The median period from the diagnosis of endometrioma to clear cell carcinoma diagnosis was 50 months (range, 12–213 months). After complete staging surgery, histological confirmation of endometriosis was possible in 35 (70%) patients. Of the 50 patients, 39 (78%) had not undergone any gynecologic surveillance until the onset of symptoms, at which time many of them presented with a rapidly growing pelvic mass (median 10 cm, range 4.6–25 cm). With the exception of 2 patients, all cancer diagnoses were made when the patients were in their late thirties, and median tumor size was found to increase along with age. Asymptomatic patients (n=11) who had regular gynecologic examinations were found to have a relatively smaller tumor size, lesser extent of tumor spread, and lower recurrence rate (P=0.011, 0.283, and 0.064, respectively). The presence of endometriosis was not related to the prognosis.

Conclusion

Considering the duration of malignant transformation and the timing of cancer diagnosis, active surveillance might be considered from the age of the mid-thirties, with at least a 1-year interval, in patients with asymptomatic endometrioma.

Incidence of IP and risk of malignant transformation in the Swedish population 1960-2010

The true incidence of inverted papilloma (IP) is not yet known. From hospital-based studies, its incidence has been estimated to approximately 0.5/100,000 person years. Earlier hospital case studies have shown that IP can undergo a malignant transformation in 1-53 %. The frequency of its malignant transformation on a population basis is unknown. To our knowledge, no standardised incidence ratio (SIR) has been reported for malignancies among IPs. This study aims to investigate these incidences on a population basis. Using the data from the Swedish Cancer Registry (SCR), we have identified patients with IP and patients with Squamous Cell Carcinoma (SCC) diagnosed between 1960 and 2010 in Sweden. Incidence of IP and incidence of SCC among patients with IP and SIR were analyzed. Eight hundred and fourteen patients with IP were identified. The incidence of IPs reported to the SCR increased from 1960 to 2010. In this cohort, SCC was overrepresented, as compared with the general population. The incidence of IP in the Swedish population seems to have increased.

Molecular Targeting of ERKs/RSK2 Signaling Axis in Cancer Prevention

RSK2 is a downstream signaling protein of ERK1 and ERK2 and plays a key role in physiological homeostasis. For this reason, RSK2 is a highly conserved protein among the p90RSK family members. In its location in the signaling pathway, RSK2 is a kinase just upstream of transcription and epigenetic factors, and a few kinases involved in cell cycle regulation and protein synthesis. Moreover, activation of RSK2 by growth factors is directly involved in cell proliferation, anchorage-independent cell transformation and cancer development. Direct evidences regarding the etiological roles of RSK2 in cancer development in humans have been published by our research group illustrating that elevated total- and phospho-RSK2 protein levels mediated by ERK1 and ERK2 are higher in skin cancer tissues compared to normal skin tissues. Notably, it has been shown that RSK2 ectopic expression in JB6 Cl41 cells induces cell proliferation and anchorage- independent cell transformation. Importantly, knockdown of RSK2 suppresses Ras-mediated foci formation and anchorage-independent colony growth of cancer cells. Kaempferol is a one of the natural compounds showing selectivity in inhibiting RSK2 activity in epidermal growth factor-induced G1/S cell cycle transition and cell transformation. Thus, ERKs/RSK2 signaling axis is an important target signaling molecule in chemoprevention.

[Osteosarcomatous dedifferentiated chondrosarcoma]

A secondary peripheral chondrosarcoma (SPC) evolving from an osteochondroma is rare, but it has been described several times. The development of an osteosarcomatous dedifferentiated chondrosarcoma in a locally recurrent SPC is extremely rare. The following case report of a 46-year-old man demonstrates and discusses this phenomenon.

YB-1 transforms human mammary epithelial cells through chromatin remodeling leading to the development of basal-like breast cancer

There is growing evidence that cancer-initiation could result from epigenetic changes. Y-box binding protein-1 (YB-1) is a transcription/translation factor that promotes the formation of tumors in transgenic mice; however, the underlying molecular events are not understood. To explore this in a human model system, YB-1 was expressed in mammary epithelial cells under the control of a tetracycline-inducible promoter. The induction of YB-1 promoted phenotypes associated with malignancy in three-dimensional breast acini cultures. This was attributed to YB-1 enhancing the expression and activity of the histone acetyltransferase p300 leading to chromatin remodeling. Specifically, this relaxation of chromatin allowed YB-1 to bind to the BMI1 promoter. The induction of BMI1 engaged the Polycomb complex resulting in histone H2A ubiquitylation and repression of the CDKN2A locus. These events manifested functionally as enhanced self-renewal capacity that occurred in a BMI1-dependent manner. Conversely, p300 inhibition with anacardic acid prevented YB-1 from binding to the BMI1 promoter and thereby subverted self-renewal. Despite these early changes, full malignant transformation was not achieved until RSK2 became overexpressed concomitant with elevated human telomerase reverse transcriptase (hTERT) activity. The YB-1/RSK2/hTERT expressing cells formed tumors in mice that were molecularly subtyped as basal-like breast cancer. We conclude that YB-1 cooperates with p300 to allow BMI1 to over-ride p16(INK4a) -mediated cell cycle arrest enabling self-renewal and the development of aggressive breast tumors.

[Potentially malignant character of oral lichen planus and lichenoid lesions]

INTRODUCTION

Many authors have reported the possible malignant transformation of oral lichen. The incidence of this event remains controversial. Many authors make a distinction between the "true" oral lichen planus (OLP) and lichenoid lesions (LL) according to the WHO clinical and histological classification. For these authors an increased risk of development of oral cancer could occur only on LL. Our aim was to check this hypothesis on a cohort followed for 10 years.

MATERIAL AND METHODS

We included patients who were referred to our team for the first time between 1995 and 1997, still followed in 2010, with a histological diagnosis of buccal lichen planus. We classified lesions as OLP or LL according to the WHO clinical and histological classification: the two clinical criteria for OLP were a reticulated aspect and bilateral and symmetric lesions. Three histological criteria were necessary for the diagnosis: dense inflammatory infiltrate in the upper lamina propria, liquefaction degeneration of basal keratinocytes, and no signs of dysplasia. The final diagnosis was OLP, when all clinical ad histological criteria were met otherwise it was LL. We studied the patient's outcome between their first consultations and May 2010.

RESULTS

Thirty-two patients, whose data was available, met inclusion criteria. Eight were diagnosed with OLP and 24 with LL. The mean follow-up was 164 months [154-183]. No oral cancer was observed in the OLP group. Two patients in the LL group presented with oral cancer after 45 and 143 months of follow-up.

DISCUSSION

Malignant transformations were observed only in the LL group. Our results correlate with those of Van Der Meij et al. published in 2006. The strict use of the WHO diagnostic criteria seems to allow identifying patients at risk of developing oral cancer (LL) and others with only a benign course of this chronic oral mucosal disease. These results need to be confirmed by prospective multicentric studies.