The role of chromosome 8p22 deletion for predicting disease progression and pathological staging in prostate cancer

The role of macrophage scavenger receptor 1 (MSR1) in inflammatory disorders and cancer

Macrophage scavenger receptor 1 (MSR1), also named CD204, holds key inflammatory roles in multiple pathophysiologic processes. Present primarily on the surface of various types of macrophage, this receptor variably affects processes such as atherosclerosis, innate and adaptive immunity, lung and liver disease, and more recently, cancer. As highlighted throughout this review, the role of MSR1 is often dichotomous, being either host protective or detrimental to the pathogenesis of disease. We will discuss the role of MSR1 in health and disease with a focus on the molecular mechanisms influencing MSR1 expression, how altered expression affects disease process and macrophage function, the limited cell signalling pathways discovered thus far, the emerging role of MSR1 in tumour associated macrophages as well as the therapeutic potential of targeting MSR1.

MicroRNA-383 located in frequently deleted chromosomal locus 8p22 regulates CD44 in prostate cancer

A major genomic alteration in prostate cancer (PCa) is frequent loss of chromosome (chr) 8p with a common region of loss of heterozygosity (LOH) at chr8p22 locus. Genomic studies implicate this locus in the initiation of clinically significant PCa and with progression to metastatic disease. However, the genes within this region have not been fully characterized to date. Here we demonstrate for the first time that a microRNA component of this region –miR-383- is frequently downregulated in prostate cancer, plays a critical role in determining tumor initiating potential and is involved in prostate cancer metastasis via direct regulation of CD44, a ubiquitous marker of PCa tumor initiating cells (TICs)/ stem cells. Expression analyses of miR-383 in PCa clinical tissues established that low miR-383 expression is associated with poor prognosis. Functional data suggests that miR-383 regulates PCa tumor initiating/ stem-like cells via CD44 regulation. Ectopic expression of miR-383 inhibited tumor initiating capacity of CD44+ PCa cells. Also, ‘anti-metastatic’ effects of ectopic miR-383 expression were observed in a PCa experimental metastasis model. In view of our results, we propose that frequent loss of miR-383 at chr8p22 region leads to tumor initiation and prostate cancer metastasis. Thus, we have identified a novel finding that associates a long observed genomic alteration to PCa stemness and metastasis. Our data suggests that restoration of miR-383 expression may be an effective therapeutic modality against PCa. Importantly, we identified miR-383 as a novel PCa tissue diagnostic biomarker with a potential that outperforms that of serum PSA.

Chromosome 8p deletions and 8q gains are associated with tumor progression and poor prognosis in prostate cancer

PURPOSE

Deletions of 8p and gains of 8q belong to the most frequent cytogenetic alterations in prostate cancer. The target genes of these alterations and their biological significance are unknown.

EXPERIMENTAL DESIGN

To determine the relationship between chromosome 8 changes, and prostate cancer phenotype and prognosis, a set of 1.954 fully annotated prostate cancers were analyzed in a tissue microarray format by fluorescence in situ hybridization.

RESULTS

Both 8p deletions and 8q gains increased in number during different stages of prostate cancer progression. 8p deletions/8q gains were found in 26.1%/4.8% of 1,239 pT(2) cancers, 38.5%/9.8% of 379 pT(3a) cancers, 43.5%/8.9% of 237 pT(3b) cancers, 40.7%/14.8% of 27 pT(4) cancers, 39.1%/34.8% of 23 nodal metastases, 51.9%/33.3% of 27 bone metastases, and 45.5%/59.9% of 22 hormone refractory cancers (P < 0.0001 each). Both 8p deletions and 8q gains were also significantly associated with high Gleason grade and with each other (P < 0.0001 each). In primary tumors, 8p deletions were seen in only 27.3% of 1,882 cancers without 8q gain but in 57.4% of 122 tumors with 8q gain (P < 0.0001). Among cancers treated with radical prostatectomy, 8p deletions (P = 0.003) and 8q gains (P = 0.02) were associated with biochemical tumor recurrence. However, multivariate analysis (including prostate-specific antigen, pT/pN stage, Gleason score, and surgical margin status) did not reveal any statistically independent effect of 8p or 8q alterations on biochemical tumor recurrence.

CONCLUSIONS

8p deletions and 8q gains are relatively rare in early stage prostate cancer but often develop during tumor progression. The prognostic effect does not seem to be strong enough to warrant clinical application.

Assessment of aberrations on chromosome 8 in prostatic atrophy

OBJECTIVE

To systematically examine the genetic alterations on chromosome 8 in prostate epithelia deriving from atrophic areas, and to compare these alterations with those of cells derived from prostatic intraepithelial neoplasia (PIN) and prostate cancer in the same organ.

MATERIAL AND METHODS

Tissue microarrays were constructed from 50 patients with histologically different tissues, including normal, PIN, atrophy and cancer lesions. Control samples were obtained from 10 patients who died from causes other than prostate cancer. Multicolour DNA probes for 8p22, centromere 8 and 8q24 were used to detect genetic alterations by fluorescence in situ hybridisation analysis.

RESULTS

Chromosomal alterations were detected on chromosome 8 in all analysed tissues. Including all observed signal patterns, a gradual increase of nuclei with loss of 8p22 was detected in normal (16%), in atrophy (21%), in PIN (25%) and in cancer tissue (31%), and there was gain in 8q24 in normal tissue (10%), in atrophy lesions (19%), in PIN (21%) and in cancer (27%). Generally, in all three lesion types the percentage of cells with 8q24 gain was significantly lower than the percentage of cells with loss of 8p22.

CONCLUSION

This investigation confirms the presence of severe chromosomal aberrations in the epithelium of the atrophic glands of the prostate. The aberrations are the same those that can be found in PIN and in prostate cancer. These findings confirm the genetic instability of the cells in the atrophic areas of the prostate, which can be a target for further injuries, leading to prostate cancer.

Molecular biological analysis of the heterogeneous prostate cancer group Gleason score 7

BACKGROUND

On the basis of a multicolor-FISH test we aimed at verifying whether there is any molecular biological background for the different behavior of Gleason Score 7 prostate cancer (PCa).

PATIENTS AND METHODS

Biopsies of 44 patients with histological verified PCa, 20 with Gleason score 3 + 4 (group A) and 24 with 4 + 3 (group B), were analyzed using FISH.

RESULTS

In group A, FISH detected a unique gain of 8q24 in 2 patients (10.0%) and a unique loss of 8p22 in 9 patients (45.0%). No concurrent loss and gain of both sites were found in this group. Of group B (4 + 3) a unique loss of 8p22 was observed in 14 patients (58.3%) and a concurrent loss of 8p22 and gain of 8q24 in 6 patients (25.0%).

CONCLUSION

Different molecular genetic patterns could explain the different biological behavior of the 2 groups. The analysis of chromosomal aberrations could therefore influence the clinical decision process in the future.

Multiple abnormalities detected by dye reversal genomic microarrays in prostate cancer: a much greater sensitivity than conventional cytogenetics

Prostate cancer remains the most common male malignancy in Western countries, yet limited information exists regarding genetic changes and clinical correlations. The advent of comparative genomic hybridization microarray (GM) technology has recently allowed for precise screening of DNAs for genetic copy number changes; this offers an advantage over previous techniques, including conventional cytogenetics. A problem with cytogenetic prostate cancer analysis has been the study of the appropriate cell types because this is a highly heterogeneous tumor. We have performed GM using the Spectral Genomics Inc. dye reversal platform on 20 primary prostate tumors. These tumor samples were from frozen tissue collected over the last 10 years and multiple clinical parameters, including follow-up were collected on these patients; cytogenetic analysis was previously attempted on all patients. Eighty percent (16/20) of specimens showed copy number changes, 65% of which were losses and 35% were gains of genetic material. The most common changes observed were loss of an interstitial region of 2q (8 cases, 40%), followed by loss of interstitial 6q (6 cases, 30%), loss at 8p and 13q (5 cases each, 25%), gain at 3p and loss at 5q, 16q, and Xq (4 cases each, 20%), and gain at 8p (3 cases, 15%). There was evidence of correlation of loss at 5q with a positive node status. Cytogenetic studies on these same patients only detected clonal changes in 40% (8/20) specimens and did not detect the majority of abnormalities seen by the GM technique. We propose this technology for the evaluation of prostate and other heterogeneous cancers as a rapid and efficient way to detect genetic copy number changes.