C-myc oncogene expression in anal squamous neoplasia

Ras and C-Myc Oncoproteins during Tumor Progression in the Uterine Cervix

Aims and background

Altered oncogenic activity is a feature associated with many malignant and premalignant conditions. Among the many oncogenes, ras and myc are commonly altered in many tumors. This study aims to evaluate the expression of ras and c-myc oncoproteins in a total of 204 cervical tissue samples, including premalignant and malignant lesions as well as apparently normal cervical tissue.

Methods and study design

Mouse monoclonal antibodies against the three mammalian ras gene products (c-H-ras, c-K-ras, c-N-ras) and the c-myc protein were used to evaluate oncoprotein expression by immunocytochemistry.

Results

None of the samples analyzed displayed immunoreactivity for H-ras and K-ras. Normal cervical epithelium showed minimal immunoreactivity for N-ras with about 33% of the samples expressing the protein. More conspicuous expression in normal tissue was displayed by c-myc, with about 90% of the samples expressing the protein (mean value of cells positive = 34%). The immunoreactivity for N-ras increased with increasing histological abnormality from low-grade squamous intraepithelial lesions (SIL) to invasive carcinoma. Increased immunoreactivity for N-ras was evident in the basaloid cells of malignant lesions, with the maximum value of 66% found in poorly differentiated squamous cell carcinoma (PDSCC). The percentage of nuclei positive for c-myc also showed a gradual increase from low-grade SIL onwards, the highest positivity being found in PDSCC, where the mean value was 85%. Statistical analysis revealed a good correlation between the expression of N-ras (r = 0.8922, P = 0.001) and c-myc (r = 0.8856, P =0.001) and various histological stages of tumor progression in the cervical epithelium.

Conclusions

These results therefore suggest that c-myc and N-ras oncoproteins are important during tumor progression in the uterine cervix.

Association of p62/SQSTM1 excess and oral carcinogenesis

p62/SQSTM1 (sequestosome1) has never been evaluated in oral epithelium. In order to clarify the role of p62/SQSTM1 in carcinogenesis in oral epithelium, both p62/SQSTM1 and Nrf2 were immunohistochemically evaluated in 54 carcinomas and 14 low grade dysplasias. p62/SQSTM1 knockdowns were also designed in oral cancer cells, and we analyzed the Nrf2 pathway, GSH contents and ROS accumulation. The association between p62/SQSTM1 excess and prognosis was addressed in a clinical cohort of oral carcinoma cases. p62/SQSTM1 excess was more obvious in carcinomas, but Nrf2 was abundant in almost all samples of the oral epithelium. In oral carcinoma cells, p62/SQSTM1 knockdown did not affect the Nrf2-Keap1 pathway but did significantly reduce GSH content with subsequent ROS accumulation, and caused cell growth inhibition in the irradiated condition. Finally, p62/SQSTM1 excess was associated with poor prognosis in a clinical cohort. In oral epithelial carcinogenesis, p62/SQSTM1 excess played a role in GSH induction rather than Nrf2 accumulation, and may cause resistance to cytotoxic stresses such as radiation or chemotherapy. Immunohistochemical evaluation of p62/SQSTM1 may be a potential significant marker to identify early carcinogenesis, chemo-radiotherapeutic resistance or poor prognosis of oral squamous cell carcinomas.

Anal intraepithelial neoplasia and other neoplastic precursor lesions of the anal canal and perianal region

Anal cancer is rare and this helps to explain why anal pre-neoplastic conditions are poorly understood, especially with regard to their natural history and management. Anal intraepithelial neoplasia is closely linked to human papillomavirus infection and is particularly common in homosexuals and in immunosuppressed patients, especially those with HIV/AIDS. The high regression rates of low-grade anal intraepithelial neoplasia may simply reflect inconsistent pathologic reporting. Higher grades of anal intraepithelial neoplasia may remain static for long periods of time in immunocompetent patients, but those with HIV/AIDS show early and rapid malignant transformation. In general, most anal pre-neoplastic conditions are best diagnosed by biopsy and treated by surgical excision, although local recurrence is a problem. In anal Paget's disease, it is important to ascertain, at the time of diagnosis, whether it is due to a primary in-situ apocrine-type of neoplasia of the anus or if the disease is secondary to an invasive primary carcinoma of the rectum.

Anal intraepithelial neoplasia

Background

Anal intraepithelial neoplasia (AIN) is believed to be a precursor of anal squamous cell cancer and its incidence is rising in high-risk groups, particularly those infected with the human immunodeficiency virus (HIV). The natural history of AIN is unclear and management strategies are lacking.

Methods

This review is based on a literature search (Medline and PubMed) with manual cross-referencing of all articles related to AIN.

Results and conclusions

The aetiology of AIN is intricately linked with human papilloma viruses. The pathological processes involved in the progression of AIN are becoming clearer but the natural history, particularly the rate of progression to invasive cancer, remains unknown. There is no standard management for AIN and this is mainly due to difficulties in both diagnosis and treatment. A variety of treatment options have been tried with varying success. Surgery is associated with significant recurrence, particularly in HIV-positive patients. Non surgical approaches with imiquimod, photodynamic therapy and vaccination are appealing, and further work is required. Long-term follow-up of these patients is essential until the natural history of AIN becomes clearer.

Prognostic factors in anal carcinoma

The pathologist's role in the evaluation of patients with anal squamous carcinoma is now largely restricted to establishing the diagnosis on small biopsies. Staging is performed by imaging techniques and grading is uncertain as the biopsy may not be representative of the whole tumour. Histological subtyping is unreliable and has not been proven to be of prognostic significance. A considerable effort resulting in nearly 50 reports on cytogenetic, flow cytometric, immunohistochemical and other investigations has given new insight into pathogenesis but little guidance with regard to the individual prognosis or choice of treatment. It is concluded that future research should concentrate on larger, probably multicentre series using standardised methods and criteria for evaluation.

Guidelines for anal cytology--to make cytological diagnosis and follow up much more reliable

Anal intraepithelial neoplasia is a difficult diagnostic and management problem, particularly when it occurs in women with synchronous or metachronous genital intraepithelial neoplasia. Diagnosis and follow up by colposcopy is too specialized for widespread use, and although anal cytology has been used before it has been thought of as too inconsistent for practical application. This study standardized collection of specimens and investigated interobserver variation. The aim of the study was to determine whether observers could reliably distinguish high grade anal intraepithelial neoplasia from other conditions. Standardized collection of anal preparations was achieved in the host centre. A meeting of experienced cytopathologists was convened to agree guidelines for anal cytology. These guidelines were sent to the panel of six observers who were subsequently circulated with 30 cytopathological preparations in random order and asked to report them all. The results were collected and processed centrally. Four individuals were in complete agreement about those preparations which were inadequate for reporting, but two others had a lower threshold for rejecting preparations as inadequate. There was agreement between the observers in over 95% of cases in distinguishing high grade intraepithelial neoplasia from other cytological conditions. Kappa values range from 0.66 to 1.00. This study demonstrates that the provision of guidelines for the interpretation of anal cytopathological preparations can result in a high degree of interobserver agreement about the clinically important distinction between high grade anal intraepithelial neoplasia and other conditions. Anal cytology is a more useful technique for diagnosis and follow up of 'at risk' individuals than has previously been suggested, and should be utilized more widely in this group of patients.

Neoplasms of the anus

Anal cancers can be grouped into three major categories. First, anal margin lesions are usually well-differentiated, keratinized squamous cell carcinomas that are amenable to local treatment measures. Second, anal canal cancers distal to the dentate line are mostly epidermoid, nonkeratinizing, moderately differentiated tumors. They are usually best treated with a multimodality approach using chemoradiotherapy and reserving surgery for clinical failures. Third, cancers arising in the ATZ are usually adenocarcinomas, and their treatment depends upon local factors. APR is in order for locally aggressive lesions, but newer protocols are studying multimodality therapy for this entity as well. Other, less common cancers of this region should be evaluated based upon their biologic potential and local involvement, with treatments selected accordingly.

Anal carcinoma--a histological review

Epidemiological evidence of an association between anal carcinoma and symptomatic HIV-related disease suggests that the number of cases of this disease may increase significantly over the next few years. The role of oncogenic HPV types in the pathogenesis of anal carcinoma is substantiated by both epidemiological evidence that tumours are associated with a past history of anal warts and by experimental evidence showing that over 85% of tumours contain HPV 16/18 DNA on PCR. The physical state of the virus in the tumour cell genome is currently under investigation, and cellular interactions between HPV, HIV and other sexually transmitted viruses require further research. Clinical studies have shown that patients with anal warts and those who are HIV positive also show an increased tendency to develop dysplasia within the anal epithelium. However, the malignant potential of dysplasia remains unclear and, it presents problems in management, particularly when multifocal and high grade. Problems in classification of anal carcinomas involve both the site of the tumours and the histological appearance. Despite the difficulties which exist in estimating the origin of a tumour from canal or margin, this information does appear to have clinical significance and should therefore continue to be assessed. Recent morphological and keratin studies have emphasized the heterogeneity of these tumours and have revealed a similar heterogeneous profile of keratin expression in the normal anal epithelium. These results support the body of opinion which suggests that, with the exception of small cell carcinoma and adenocarcinoma, anal carcinomas should be considered as squamous cell tumours which are able to display a range of further morphological characteristics within which ductal differentiation and mucin production appear to carry the worst prognosis. Although there is no universally accepted staging system for anal carcinoma, depth of invasion and extent of spread at the time of diagnosis are the most important clinical factors determining survival and response to therapy. Randomized clinical trials are now under way to compare the outcome of various combinations of radiotherapy and chemotherapy, which have replaced radical surgery as a first line treatment and resulted in a significant decrease in patient morbidity from this disease.

Apoptosis in bladder cancer as related to standard prognostic factors and prognosis

Four hundred cases of transitional cell bladder cancer were reviewed by light microscopy for the presence of apoptotic cells in the primary tumour biopsy specimens. The number of apoptotic cells/mm2 of neoplastic epithelium (apoptotic index, AI) was related to various histological features and prognosis. AI was related significantly to high T-category, high grade, DNA aneuploidy, large nuclear morphometric variable values, and high proliferation rate of cancer cells. Tumours showing overexpression of p53 oncoprotein in over 10 per cent of the nuclei had significantly higher AI values than p53-negative tumours. Multivariate regression analysis showed that AI was independently predicted by mitotic index, mean nuclear area, and papillary status. Progression, recurrence-free survival, and survival of superficial tumours were all related significantly to AI. In multivariate survival analysis, T-category, papillary status, grade, and mitotic index had independent prognostic value, while the recurrence-free survival of Ta-T1 tumours was related independently to AI. The results show that AI is related particularly to mitotic activity in transitional cell bladder tumours, while AI as assessed by light microscopy hardly has any independent prognostic significance.