Molecular markers for diagnosis and prognosis

Molecular markers in oral lichen planus: A systematic review

Oral lichen planus (OLP) is a chronic inflammatory mucosal disease that is usually detected in 0.5–2.2% of the human population. Among these, only 0.5–2.9% of the lesions progress to carcinoma. However, there are no prognostic markers available presently to recognize the increased risk in malignant transformation of the lesions. Selected markers for cell proliferation, adhesion, apoptosis and lymphocytic infiltration were analyzed by immunohistochemistry in addition to static cytometry for DNA content. The concept linking OLP and oral squamous cell carcinoma states that chronic inflammation results in crucial DNA damage, which further progresses to development of carcinoma. Even though in the past decade, enormous information has been accumulated on malignant potential of OLP, its transformation still remains unclear. Hence, the purpose of this article was to review cellular and molecular markers to understand the pathogenesis of OLP and its progression toward malignancy.

Cannabinoid receptor-2 immunoreactivity is associated with survival in squamous cell carcinoma of the head and neck

The prediction of progression of individual tumours, prognosis, and survival in squamous cell carcinoma (SCC) of the head and neck is difficult. Cannabinoid-1 (CB1) and cannabinoid-2 (CB2) receptor expression is related to survival in several types of cancer, and the aim of this study was to find out whether the expression of CB1 and CB2 receptors is associated with survival in primary SCC of the head and neck. We made immunohistochemical analyses of the cannabinoid receptors on tissue arrays from 240 patients with the disease. Receptor immunoreactivity was classified as none, weak, moderate, or strong staining. Overall survival and disease-specific survival were plotted using Kaplan-Meier survival curves. A multivariate Cox proportional hazard model was created with all the relevant clinical and pathological features. Strong immunoreactivity of the CB2 receptor was significantly associated with reduced disease-specific survival (p=0.007). Cox-proportional hazard ratio (HR) showed that CB2 receptor immunoreactivity contributed to the prediction of survival (HR 3.6, 95% CI 1.5-8.7, p=0.004). Depth of invasion (HR 2.2, 95% CI 1.2-4.2, p=0.01) and vascular invasion (HR 2.5, 95% CI 1.4-4.5, p=0.001) were also associated with survival.

Expression of epidermal growth factor receptor (EGFR) and Ki67 in feline oral squamous cell carcinomas (FOSCC)

The aims of this study were to establish expression of epidermal growth factor receptor (EGFR) and Ki67 in 67 archived biopsy samples of feline oral squamous cell carcinomas (FOSCCs) and to establish if the expression of either markers was predictive of survival. Samples were immunohistochemically labelled for the two proteins and scored. Statistical analyses of data, including Kaplan-Meier survival curves, were performed. All samples expressed both markers although levels differed between samples. Median overall survival was 46 days and 1-year survival was 5%. There was no correlation between Ki67 and EGFR scores (Pearson's correlation coefficient, P = 0.861). Low cellular proliferation (low Ki67 score) was positively correlated with an overall longer survival (Log Rank, P = 0.02) and a trend towards better survival for the high EGFR group was observed (Log Rank, P = 0.076). Ki67 and EGFR immunostaining in FOSCC may be of value as biochemical markers for screening of biopsies from cases of FOSCC.

The phosphatase and tensin homologue deleted on chromosome 10 mediates radiosensitivity in head and neck cancer

Background:

For locally advanced squamous cell carcinoma of the head and neck (HNSCC), the recurrence rate after surgery and postoperative radiotherapy is between 20 and 40%, and the 5-year overall survival rate is ∼50%. Presently, no markers exist to accurately predict treatment outcome. Expression of proteins in the human epidermal growth factor receptor (EGFR) pathway has been reported as a prognostic marker in several types of cancer.

Methods:

The aim of this study was to investigate the prognostic value of proteins in the EGFR pathway in HNSCC. For this purpose, we collected surgically resected tissue of 140 locally advanced head and neck cancer patients, all treated with surgery and postoperative radiotherapy.

Results:

In a multivariate analysis, expression of the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was significantly related to worse locoregional control (LRC; HR: 2.2, 95% CI: 1.1–4.6; P=0.03), independent of lymph node metastases (HR: 5.6, 95% CI: 1.2–27.4; P=0.03) and extranodal spread (HR: 2.7; 95% CI: 1.2–6.5; P=0.02). In vitro clonogenic radiosensitivity assays confirmed that overexpression of PTEN resulted in increased radioresistance.

Conclusion:

Our study is the first report showing that expression of PTEN mediates radiosensitivity in vitro and that increased expression in advanced HNSCC predicts worse LRC.

The antiangiogenic agent ZD4190 prevents tumour outgrowth in a model of minimal residual carcinoma in deep tissues

Background:

Tumour cells may persist at the operative site after seemingly adequate surgery. Radiotherapy is often given in an attempt to prevent repopulation, but this modality cannot be relied upon to prevent locoregional recurrence. An alternative strategy is to take advantage of the requirement of tumour cells to develop an independent blood supply and block this process to prevent recurrence.

Methods:

In this study, we evaluate the effect of the angiogenesis inhibitor, ZD4190, using a rodent model of residual carcinoma in deep tissues, mimicking the clinical scenario where low numbers of malignant cells persist at the operative site.

Results:

The tumour burden that could be eliminated was dependent on the site where the cells were implanted. Immediate treatment with ZD4190 prevented outgrowth of up to 2.5 × 10⁵ cells in the rectus muscle and 1 × 10⁵ in the gastrocnemius, whereas control animals developed large tumours. When more than 2.5 × 10⁶ cells were implanted into the rectus or 1 × 10⁶ into the gastrocnemius and treatment was maintained for 3 weeks, the carcinomas that developed in ZD4190-treated animals showed a reduced microvessel density and increased necrosis when compared with the vehicle-treated controls, but an infiltrative growth pattern was common.

Conclusion:

These findings suggest that antiangiogenic agents have a role to play in preventing outgrowth of residual carcinoma and are likely to be most effective when the tumour burden is minimal.

Distinctive clinicopathological associations of amplification of the cortactin gene at 11q13 in head and neck squamous cell carcinomas

Amplification of the 11q13 region is a prevalent genetic alteration in head and neck squamous cell carcinoma (HNSCC). We investigated the clinical significance of cortactin (CTTN) and cyclin D1 (CCND1) amplification in both malignant transformation and tumour progression. CTTN and CCND1 amplification was analysed by differential and real-time PCR in a prospective series of laryngeal/pharyngeal carcinomas and archival premalignant tissues. CTTN mRNA and protein expression were respectively determined by real-time RT-PCR and immunohistochemistry, and correlated with gene status. Molecular alterations were associated with clinicopathological parameters and disease outcome. CTTN and CCND1 amplifications were respectively found in 75 (37%) and 90 (45%) tumours. Both correlated with advanced disease; however, only CTTN amplification was associated with recurrence and reduced disease-specific survival (p = 0.0022). Strikingly, CTTN amplification differentially influenced survival depending on tumour site (p = 0.0001 larynx versus p = 0.68 pharynx) and was an independent predictor of reduced survival in the larynx (p = 0.04). CCND1 amplification was detected in early tumourigenesis and increased with the severity of dysplasia. Importantly, CTTN amplification was only found in high-grade dysplasias that progressed to invasive carcinoma. CTTN gene status strongly correlated with mRNA and protein expression. Furthermore, CTTN overexpression correlated significantly with reduced disease-specific survival (p = 0.018). Taken together, these data indicate that CTTN may serve as a valuable biomarker to identify patients with laryngeal tumours at high risk of recurrence and poor outcome.

Pharmacoepigenomics in colorectal cancer: a step forward in predicting prognosis and treatment response

Despite therapeutic innovations and increasing education on lifestyle to prevent colorectal cancer, it is still one of the most common cancer types, and for men the second cause of cancer-related death. Lately, much attention has been given to identify molecular markers involved in colorectal cancer prognosis and treatment with the aim to develop a more accurate classification system based on (epi)genetic alterations and, in addition, find markers that could potentially enhance management of colorectal cancer by predicting treatment response in advance. Although many genetic markers have been claimed to have prognostic or predictive influence, results are often inconclusive and, with some exception, they are not used in standard practice. Epigenetic alterations have received less attention although they are probably even more interesting as they can potentially be reversed through drug treatment. This review describes the current knowledge on the prognostic and predictive value of epigenetic markers in colorectal cancer.

Oral cancer diagnosis by mechanical phenotyping

Oral squamous cell carcinomas are among the 10 most common cancers and have a 50% lethality rate after 5 years. Despite easy access to the oral cavity for cancer screening, the main limitations to successful treatment are uncertain prognostic criteria for (pre-)malignant lesions. Identifying a functional cellular marker may represent a significant improvement for diagnosis and treatment. Toward this goal, mechanical phenotyping of individual cells is a novel approach to detect cytoskeletal changes, which are diagnostic for malignant change. The compliance of cells from cell lines and primary samples of healthy donors and cancer patients was measured using a microfluidic optical stretcher. Cancer cells showed significantly different mechanical behavior, with a higher mean deformability and increased variance. Cancer cells (n approximately 30 cells measured from each patient) were on average 3.5 times more compliant than those of healthy donors [D(normal) = (4.43 +/- 0.68) 10(-3) Pa(-1); D(cancer) = (15.8 +/- 1.5) 10(-3) Pa(-1); P < 0.01]. The diagnosis results of the patient samples were confirmed by standard histopathology. The generality of these findings was supported by measurements of two normal and four cancer oral epithelial cell lines. Our results indicate that mechanical phenotyping is a sensible, label-free approach for classifying cancer cells to enable broad screening of suspicious lesions in the oral cavity. It could in principle be applied to any cancer to aid conventional diagnostic procedures.

Molecular diagnostic testing in malignant gliomas: a practical update on predictive markers

Advances in understanding the molecular underpinnings of cancer and in molecular diagnostic technologies have changed the clinical practice of oncologic pathology. The development of targeted therapies against specific molecular alterations in cancer further portends changes in the role of the pathology laboratory to guide such custom therapies. To reconcile the flood of scientific discoveries in this area, the promises of highly touted novel therapeutics, and the practicality of applying this knowledge to the day-to-day practice of clinical neuropathology, the present review highlights the operative differences between diagnostic, predictive, and prognostic markers, and discusses issues surrounding the transition of prospective biomarkers to routine laboratory implementation. This review focuses on 3 predictive molecular markers that are either in clinical use or are contemplated for use in the evaluation of malignant gliomas: assessment of 1p/19q loss in oligodendroglial tumors, examination of O6-methylguanine DNA methyltransferase promoter methylation status in glioblastomas, and molecular dissection of the epidermal growth factor receptor-phosphatidylinositol 3-kinase pathway in glioblastomas. Implementation of such predictive markers is not straightforward and requires critical review of the available literature and attention to practical laboratory, compliance, financial, and clinical management issues.

Methylation of the p16(INK4a) promoter region in telomerase immortalized human keratinocytes co-cultured with feeder cells

Human keratinocytes grown in co-culture with fibroblast feeder cells have an extended in vitro lifespan and delayed accumulation of the tumor suppressor protein p16(INK4a) when compared to the same cells grown on tissue culture plastic alone. Previous studies have indicated that human keratinocytes can be immortalized by telomerase activity alone when grown in co-culture with feeder cells, suggesting that loss of the p16(INK4a)/Rb pathway is not required for immortalization. Using two independent human keratinocyte cell strains, we found that exogenous telomerase expression and co-culture with feeder cells results in efficient extension of lifespan without an apparent crisis. However, when these cells were transferred from the co-culture environment to plastic alone they experienced only a brief period of slowed growth before continuing to proliferate indefinitely. Examination of immortal cell lines demonstrated p16(INK4a) promoter methylation had occurred in both the absence and presence of feeder cells. Reintroduction of p16(INK4a) into immortal cell lines resulted in rapid growth arrest. Our results suggest that p16(INK4a)/Rb-induced telomere-independent senescence, although delayed in the presence of feeders, still provides a proliferation barrier to human keratinocytes in this culture system and that extended culture of telomerase-transduced keratinocytes on feeders can lead to the methylation of p16(INK4a).