HE4 suppresses the expression of osteopontin in mononuclear cells and compromises their cytotoxicity against ovarian cancer cells.

Ovarian cancers are known to evade immunosurveillance and to orchestrate a suppressive immune microenvironment. Here we examine the role of human epididymis protein 4 (HE4), an ovarian cancer biomarker, in immune evasion. Through modified subtractive hybridization analyses we have characterized the gene targets of HE4 in human peripheral blood mononuclear cells (PBMCs), and established a preliminary mechanism for HE4-mediated immune failure in ovarian tumours. Upon exposure of purified PMBCs to HE4, osteopontin (OPN) and dual-specificity phosphatase 6 (DUSP6) emerged as the most suppressed and up-regulated genes, respectively. SKOV3 and OVCAR8, human ovarian carcinoma cell lines, exhibited enhanced proliferation in conditioned media from HE4-exposed PBMCs, an effect that was attenuated by the addition of recombinant OPN or OPN-inducible cytokines [interleukin (IL)-12 and interferon (IFN)-Ɣ]. Additionally, upon co-culture with PBMCs, HE4-silenced SKOV3 cells were found to be more susceptible to cytotoxic cell death. The relationship between HE4 and OPN was reinforced further through the analysis of serous ovarian cancer patient samples. In these biopsy specimens, the number of OPN+ T cells correlated positively with progression free survival (PFS) and inversely with serum HE4 level. Taken together, these findings show that HE4 enhances ovarian cancer tumorigenesis by compromising OPN-mediated T cell activation.

Genetic analysis of head and neck squamous cell carcinoma using comparative genomic hybridisation identifies specific aberrations associated with laryngeal origin.

Head and neck squamous cell carcinoma (HNSCC) demonstrates significant differences in the biological and clinical behaviour of tumours found at different sub-sites. We investigated the genetic profiles of 68 carcinomas (larynx n=35, hypopharynx n=19, oropharynx n=14) using chromosomal comparative genomic hybridisation in order to identify sub-site specific differences. Multiple genetic aberrations were found throughout the tumour genomes, including +3q (82%), -3p (75%), +8q (66%), +5p (49%), +7q (49%), +1q (47%), -4p (46%), -11q (46%), -13q (46%), -5q (44%), +11q (43%) and +12p (43%). The mean number of chromosomal arms with at least one aberration was 15. Laryngeal carcinomas (LSCC) were found to have significantly more aberrations on chromosomal arms than oropharyngeal carcinomas (OpSCC); (mean of 17 vs. 11, respectively (p=0.011). It was noted that -4p, +8q, +12q, and -18q were significantly associated with LSCC when compared with both hypopharyngeal SCC (HpSCC) and OpSCC. HpSCC was significantly associated with -2q whereas no aberrations were found to be significantly associated with OpSCC. In conclusion a large number of common chromosomal aberrations are associated with HNSCC however in addition further aberrations are significantly associated with individual sub-sites of head and neck cancer. These aberrations may be responsible for the diverse biological behaviour of these different tumour types. Further research is required to identify the specific genes associated with these chromosomal regions and evaluate their individual impact on disease progression.

Mismatch repair, p53 and chromosomal aberrations in primary colorectal carcinomas.

Colorectal carcinoma progresses via at least two genetic pathways. Microsatellite instability, due to defective mismatch repair genes, characterizes one pathway and gross chromosomal instability another. The involvement of p53 and mismatch repair gene abnormalities within these pathways has not been fully explored. We aimed to investigate the relationships of p53 and mismatch repair gene defects on gross chromosomal aberrations detected by comparative genomic hybridization in 49 colorectal carcinomas. Tumours demonstrating loss of expression for hMLH1 or hMSH2 proteins demonstrated a highly significant attenuation in the number of gross chromosomal aberrations (p = 0.007) and were less likely to show p53 overexpression (p = 0.02). Within the mismatch repair normal tumours, p53 status did not affect the total number of chromosomal aberrations but p53 overexpression was significantly associated with a higher frequency of amplifications at 8q22-ter and at 13q21-22. Colorectal cancer demonstrates distinct molecular phenotypes and should be sub-classified accordingly.

Can a genetic signature for metastatic head and neck squamous cell carcinoma be characterised by comparative genomic hybridisation?

Survival from head and neck squamous cell carcinoma (HNSCC) has remained static for the last 20 years. The development of lymph node metastasis (LNM) significantly reduces the 5-year survival rate, thus the ability to identify tumours with the potential to metastasise would allow more aggressive treatment regimes to be directed at these patients regardless of negative clinical and radiological findings at the time of presentation. Comparative genomic hybridisation (CGH) can identify chromosomal aberrations that may lead to metastasis. DNA from 23-paired specimens of primary tumour (PT) and LNM were analysed. Nonrandom copy number changes were identified in all paired samples. Similar numbers of aberrations were identified on PT and LNM samples. The most common aberrations were 3q (90%), 8q (65%), 1q (50%), 5p (43%), 2q (41%) and 11q (41%) and deletions 3p (57%), 1p (54%), 4p (48%), 13q (48%), 11q (41%) and 10q (37%). A number of differences were also detected. No aberration was found to be preferentially associated with the LNM, although gains on 6q (48 vs 22%) and 22q (26 vs 9%) were found at higher frequencies. Clonality studies demonstrated that LNM develop from the dominant population of cells in the PT. These results were compared with two similar publications. No combination of chromosomal aberrations, as detected by CGH, was associated with metastatic progression in HNSCC.

Overexpression of Bcl-2 in squamous cell carcinoma of the larynx: a marker of radioresistance.

Squamous cell carcinoma of the larynx can be treated using radiotherapy or surgery, either alone or in combination. Radiotherapy is preferred for early-stage tumours, as it spares the larynx and therefore preserves speech and swallowing. Unfortunately, approximately 15% of tumours treated this way will prove to be radioresistant, as manifest by tumour recurrence within the original radiotherapy field over the ensuing 12 months. By causing extensive DNA damage, radiotherapy aims to induce apoptosis and tumour regression. Our hypothesis was that defects in the mechanisms that recognise DNA damage, induce cell cycle arrest or control apoptosis, either alone or in combination, may be responsible for radioresistance. We therefore undertook an immunohistochemic analysis of pretreatment biopsies of radioresistant (n = 8) and radiosensitive (n = 13) laryngeal tumours. To minimise the impact of confounding factors, strict inclusion criteria were observed; all tumours were of the glottic subsite and all recurrences developed within 12 months of radiotherapy at the site of the original tumour. The expression of key proteins involved in DNA damage recognition (p53), cell cycle arrest (ATM, p16 and p21/WAF1) and apoptosis (Bcl-2 and BAX) were studied. Ki-67 was also assessed as a marker of cell proliferation to exclude low mitotic rate as a cause of radioresistance. A statistically significant correlation was observed between overexpression of Bcl-2 and radioresistance (p = 0.003, Fisher's exact test). We hypothesise that overexpression of the anti-apoptotic protein Bcl-2 allows tumour cells with extensive radiation-induced DNA damage to continue proliferating; the absence of an appropriate apoptotic response manifests clinically as radioresistance.