BRAF mutation testing algorithm for vemurafenib treatment in melanoma: recommendations from an expert panel

The incidence of melanoma has increased rapidly over the past 30 years, and the disease is now the sixth most common cancer among men and women in the U.K. Many patients are diagnosed with or develop metastatic disease, and survival is substantially reduced in these patients. Mutations in the BRAF gene have been identified as key drivers of melanoma cells and are found in around 50% of cutaneous melanomas. Vemurafenib (Zelboraf(®) ; Roche Molecular Systems Inc., Pleasanton, CA, U.S.A.) is the first licensed inhibitor of mutated BRAF, and offers a new first-line option for patients with unresectable or metastatic melanoma who harbour BRAF mutations. Vemurafenib was developed in conjunction with a companion diagnostic, the cobas(®) 4800 BRAF V600 Mutation Test. The purpose of this paper is to make evidence-based recommendations to facilitate the implementation of BRAF mutation testing and targeted therapy in patients with metastatic melanoma in the U.K. The recommendations are the result of a meeting of an expert panel and have been reviewed by melanoma specialists and representatives of the National Cancer Research Network Clinical Study Group on behalf of the wider melanoma community. This article is intended to be a starting point for practical advice and recommendations, which will no doubt be updated as we gain further experience in personalizing therapy for patients with melanoma.

Transcriptional activation of cyclooxygenase-2 by tumor suppressor p53 requires nuclear factor-kappaB

Overexpression of cyclooxygenase-2 (Cox-2) is thought to exert antiapoptotic effects in cancer. Here we show that the tumor suppressor p53 upregulated Cox-2 in esophageal and colon cancer cell lines by inducing the binding of nuclear factor-kappaB (NF-kappaB) to its response element in the COX-2 promoter. Inhibition of NF-kappaB prevented p53 induction of Cox-2 expression. Cooperation between p53 and NF-kappaB was required for activation of COX-2 promoter in response to daunomycin, a DNA-damaging agent. Pharmacological inhibition of Cox-2 enhanced apoptosis in response to daunomycin, in particular in cells containing active p53. In esophageal cancer, there was a correlation between Cox-2 expression and wild-type TP53 in Barrett's esophagus (BE) and in adenocarcinoma, but not in squamous cell carcinoma (P<0.01). These results suggest that p53 and NF-kappaB cooperate in upregulating Cox-2 expression, promoting cell survival in inflammatory precursor lesions such as BE.

[Conjunctival tumors in children. A histopathologic study of 42 cases]

PURPOSE

The aim of this study was to describe the clinicopathological characteristics of 42 conjunctival tumors surgically removed in children.

PATIENTS AND METHODS

Records of all conjunctival tumors surgically removed in children during the 11-year period 1990-2001 were collected from the records of the Department of Ophthalmology, Edouard Herriot Hospital, Lyon. In all cases, the tumor was resected with no additional treatment. Sections of all cases were reviewed by the same pathologist.

RESULTS

A total of 42 cases (40 patients) were included in the study. The mean age of the subjects at the time of surgical excision was 10 years, with a range of 1-17 years; 45% were male. The most frequent indication for tumor removal was suspected growth. The clinical diagnosis was accurate in 91% of cases. The tumor was localized at the limbus in 57% of cases. Most tumors were pigmented nevi, accounting for 83% of the lesions. The histopathological diagnoses in decreasing order of frequency were: nevi (35), angioma (2), dermolipoma (2), dermoid (1), papilloma (1), and squamous cell carcinoma (1). In one case, the histological study revealed squamous cell carcinoma in a child suffering from xeroderma pigmentosum.

CONCLUSIONS

This retrospective study suggests that malignancy of pigmented conjunctival lesions is extremely rare in children. Although squamous cell carcinoma is rare in children, surgical excision and histological study are necessary when a conjunctival lesion is associated with xeroderma pigmentosum or immunodeficiency.

Altered expression of DNA double-strand break detection and repair proteins in breast carcinomas

AIMS

To determine whether the expression of DNA damage detection and repair proteins is frequently altered in breast carcinomas.

METHODS AND RESULTS

The expression profiles of five such proteins: ATM, p53, NBS1, MRE11 and Rad50 were analysed in 99 in-situ and invasive ductal breast carcinomas of different grades using an immunohistochemical approach, and compared with those seen in eight independent non-cancer (normal) breast samples and in the surrounding normal tissues of the breast carcinomas examined. ATM protein expression was reduced in 75% of the tumours compared with the levels found in normal tissues. Fewer tumours had reduced protein levels of the members of the MRE11, NBS1 and Rad50 (MNR) complex (31%, 46% and 28%, respectively) with p53 being over-expressed in 30%. In the majority of tumours (92%) we observed a good correlation between the expression of the three proteins of the MNR complex with low NBS1, MRE11 or Rad50 expression rarely found alone, suggesting that this event occurs subsequently to the deregulation in expression of other DNA repair proteins.

CONCLUSION

The pattern of protein changes observed supports our hypothesis that alterations in DNA double-strand break repair capacity are involved in mammary carcinogenesis.

[ARDS as an unusual presentation of bronchiolitis obliterans organizing pneumonia]

We report the case of a 46-year-old patient with liver transplantation who developed an acute respiratory distress syndrome (ARDS). The commonly associated clinical disorders, those associated with direct injury to the lung and those that cause indirect lung injury in the setting of a systemic process, were not responsible for the clinical picture. Finally, because of progressive clinical deterioration, an open-lung biopsy was performed and revealed a bronchiolitis obliterans with organizing pneumonia (BOOP). Physicians should be aware of this rare aetiology of ARDS.

Distinct pattern of TP53 mutations in squamous cell carcinoma of the esophagus in Iran

Extremely high rates of squamous cell carcinoma of the esophagus (SCCE) are observed in Iran, reflecting unknown, genetic and/or epidemiological risk factors. Among genetic alterations in SCCE, TP53 mutations are the most frequent, vary among populations, and may provide clues on etiological mechanisms. We have analysed mutations in TP53 (exons 5-8) in 98 SCCE from Iran by temporal temperature gel electrophoresis and direct sequencing. We found 58 mutations in 49 patients (50%), with a high prevalence of C to T transitions at CpG dinucleotides (29.3%). The TP53 mutation pattern in Iran was significantly different from that observed in SCCEs from high incidence areas of China and Western Europe (P=0.007). Moreover, the prevalence of mutations at A : T base pairs (transitions and transversions) was higher in men than in women (38.7% vs 11.1%, P=0.033). COX-2 overexpression was detected in 69% of the cases evaluated (24/35), without significant association with TP53 mutation. Accumulation of nitrotyrosine, a marker of protein damage by excess levels of nitric oxide, was observed in tumor cells in six of 18 [corrected] cases analysed. These results are consistent with the hypothesis that several factors are involved in TP53 mutagenesis in Iran. These factors include a baseline of chronic inflammatory stress, which may have a multiplicative impact on the sensitivity of esophageal cells to exogenous factors of risk.

TP53 mutations, amplification of P63 and expression of cell cycle proteins in squamous cell carcinoma of the oesophagus from a low incidence area in Western Europe

In Europe, high incidence rates of oesophageal squamous cell carcinoma (SCCE) are observed in western France (Normandy and Brittany) and in north-eastern Italy. Analysis of TP53 mutations in tumours from these regions has shown a high prevalence of mutations at A:T basepairs that may result from DNA damage caused by specific mutagens. However, the spectrum of TP53 mutations in regions of low incidence is unknown. We report here TP53 mutation analysis in 33 SCCE collected in Lyon, an area of low incidence. These tumours were also examined for MDM2 and P63 amplification, and for expression of p16(INK4a/CDKN2a), cyclin E, p27(Kipl)and Cox2. TP53 mutations were detected in 36% of the cases (12/33). In contrast with regions of high incidence, the mutation spectrum did not show a high prevalence of mutations at A:T base pairs. P63 was amplified in 5/32 cases tested (15.5%). No amplification of MDM2 was found. Expression studies revealed frequent loss of p16(INK4a/CDKN2a)(46%) and p27(Kipl)(25%) expression, and frequent overexpression of Cyclin E (70%) and Cox2 (42%). Overall, these results indicate that in Europe, SCCE from areas of high and low incidence present a similar pattern of molecular alterations but differ by the type of TP53 mutations.

[What do we know about ATM protein expression in breast tissue?]

The great majority of breast cancer cases are not associated with a mutated gene of high penetrance such as BRCA1, BRCA2 and TP53. Genes of low penetrance, frequently mutated in the general population, might play an important role in breast cancer development. The ATM gene, which encodes the ATM protein, mutated in the disorder ataxia telangiectasia (AT) could be such a susceptibility gene. Indeed, 1% of the general population is estimated to be AT heterozygote and females have an increased risk of developing breast cancer. The ATM protein is involved in the signalling pathway of DNA double-strand breaks. Studies on its expression in normal breast tissues have shown that ATM is expressed in the epithelial cells of breast ducts, but not in the myoepithelial cells. In sclerosing adenosis, a benign lesion of the breast, the ATM protein is expressed in both cell types whereas its expression is absent or reduced in tumour epithelial cells in about 30-50% of invasive carcinomas. Moreover, the study of the p53 status in some of these tumours has revealed that the ATM/p53 signalling pathway is frequently altered either by a very low ATM expression or by the presence of a mutated p53. It remains to be determined whether alterations in the expression of other proteins also involved in this DNA damage signalling cascade are specifically associated with breast cancer development and/or a radiosensitive phenotype seen in some breast cancer patients after radiotherapy.

[Mucosal endoscopic resections]

Endoscopic mucosectomy is a newly developed endoscopic technique allowing the resection of large fragments of digestive mucosa. The main indications of this technique are the staging and/or the treatment of superficial lesions of esophagus, stomach and colon. Resections by endoscopic mucosectomy raise specific problems of macroscopic technique and histological analysis. For correct inclusion, fragments must be pinned under a rigid support by the endoscopist. Their lateral margins must be sampled independently. The fragment must be included in totality. The histological report must indicate the depth of the resection and its quality, particularly the status of lateral and deep margins. The main difficulties of the histological analysis are due to the frequent occurrence of coagulation artefacts, which may hamper a correct interpretation of the lesions, particularly along the lateral margins. The appropriate management of endoscopic mucosal resections requires a good collaboration between endoscopists and pathologists.

Molecular and clinical differences between adenocarcinomas of the esophagus and of the gastric cardia

Adenocarcinoma of the esophagus (ADCE) with Barrett's mucosa and adenocarcinoma of the cardia (ADCC) are often reported as a single pathological entity. In this study we have used strict anatomical-pathological criteria to distinguish between these two lesions and we have investigated their differences in TP53 mutations, MDM2 gene amplification, and cytokeratin expression. DNA was extracted from the tumor areas of formalin-fixed, paraffin-embedded sections in 26 ADCC and 28 ADCE patients. TP53 mutations were detected by temporal temperature gradient electrophoresis and identified by sequencing. MDM2 amplification was assessed by differential polymerase chain reaction. The expression of cytokeratins 4, 7, and 13 was examined by immunohistochemistry. In ADCC, the male to female ratio was 1.8:1, compared to 27:1 in ADCE. Five ADCC patients had a history of other neoplasms, compared to only one ADCE patient. The two types of tumor differed in the prevalence of TP53 mutations (31% in ADCC and 50% in ADCE) and of MDM2 gene amplification (19% in ADCC and 4% in ADCE), and in the pattern of expression of cytokeratin 7 (positive in 100% of ADCE and in 41% of ADCC) and cytokeratin 13 (positive in 81% of ADCE and in 36.5% of ADCC). ADCE and ADCC differ in their clinical characteristics, in the prevalence of TP53 mutations and MDM2 amplifications, and in the patterns of cytokeratin expression. These results support the notion that ADCC and ADCE are distinct pathological entities.

TP53 mutations and MDM2 gene amplification in squamous-cell carcinomas of the esophagus in south Thailand

Squamous-cell carcinoma of the esophagus (SCCE) shows geographic variations in incidence that are thought to reflect the etiological involvement of environmental or dietary risk factors. Mutations of TP53 are frequent in SCCE, and there is evidence that both the frequency and type of these mutations may differ from one geographic area to the other. Although SCCE is relatively rare in most parts of Thailand, the province of Songkhla (south Thailand) has been described as a high-risk area for SCCE. We have analyzed 56 SCCE cases from this area for TP53 mutations by denaturing gradient gel electrophoresis (DGGE, exons 5-8) and direct DNA sequencing. The same tumors were also analyzed for MDM2 gene amplification by differential PCR. TP53 mutations were detected in 23 cases (41%). In contrast, clear amplification of MDM2 was detected in only 2 cases (4%), both of which contained wild-type TP53. Comparison with published results from other geographic areas of high SCCE incidence revealed that the spectrum of TP53 mutations in south Thailand is similar to that observed in central China (Henan Province) but clearly differs from that of SCCE from western Europe (Normandy, France; northern Italy), with more G:T transversions and fewer mutations affecting A and T base pairs. These results suggest that SCCE from south Thailand and from central China may involve similar risk factors.

TP53 mutations and MDM2 gene amplification in squamous-cell carcinomas of the esophagus in south Thailand

Squamous-cell carcinoma of the esophagus (SCCE) shows geographic variations in incidence that are thought to reflect the etiological involvement of environmental or dietary risk factors. Mutations of TP53 are frequent in SCCE, and there is evidence that both the frequency and type of these mutations may differ from one geographic area to the other. Although SCCE is relatively rare in most parts of Thailand, the province of Songkhla (south Thailand) has been described as a high-risk area for SCCE. We have analyzed 56 SCCE cases from this area for TP53 mutations by denaturing gradient gel electrophoresis (DGGE, exons 5-8) and direct DNA sequencing. The same tumors were also analyzed for MDM2 gene amplification by differential PCR. TP53 mutations were detected in 23 cases (41%). In contrast, clear amplification of MDM2 was detected in only 2 cases (4%), both of which contained wild-type TP53. Comparison with published results from other geographic areas of high SCCE incidence revealed that the spectrum of TP53 mutations in south Thailand is similar to that observed in central China (Henan Province) but clearly differs from that of SCCE from western Europe (Normandy, France; northern Italy), with more G:T transversions and fewer mutations affecting A and T base pairs. These results suggest that SCCE from south Thailand and from central China may involve similar risk factors.

Abnormal expression of the ATM and TP53 genes in sporadic breast carcinomas

The ataxia telangiectasia gene (ATM) has been implicated as a risk factor in the development of sporadic breast carcinomas. ATM protein expression was analyzed by immunohistochemistry in 17 breast carcinomas with two monoclonal antibodies whose immunohistochemical use was first validated by comparing the immunoreactivity observed in spleen samples from ataxia telangiectasia and trauma patients. In normal breast ducts, ATM showed nuclear expression in the epithelial but not in the myoepithelial cells. In contrast, this nuclear expression was absent or low in the epithelial cancer cells in 10 of 17 (59%) of the tumors studied. Allelic imbalance in the ATM gene was found in three of seven tumors examined. Two of these showed reduced ATM protein expression, but this did not correlate with the presence of ATM mutations in the tumor DNA detected by restriction endonuclease fingerprinting screening. These results suggest that the reduced ATM protein expression could be attributable, in certain tumors, to deletions or rearrangements within or close to the ATM gene. Positive p53 immunostaining was found in 10 tumors, with TP53 mutations detected in 8. Three tumors had both low ATM expression and mutated TP53. Our results indicate that in the majority (15 of 17) of the sporadic breast carcinomas examined, not only is the functionality of the ATM-p53-mediated DNA damage response compromised, but also other signaling pathways activated by these two multifunctional proteins are likely to be impaired, which could be a contributing factor to tumor development and progression.

[Pseudotumor amylosis of the bladder. Apropos of a case]

A 57 year-old patient with localized pseudo-tumoral amyloidosis of bladder is described. There was no past medical history. Hematuria was the main symptom. The treatment consisted in transurethral resection. Two recurrences occurred at 4 and at 6 years which were also treated by resections. Clinical and biological evaluation was normal. Localized pseudo-tumoral amyloidosis of the urinary tract is a rare affection of good prognosis. Lesions present as pseudo-tumoral masses which can be biopsied without any risk of hematuria. Investigations are required to eliminate a generalized amyloidosis or a malignant lymphoproliferation. Treatment should be as conservative as possible.

Lymphomatoid granulomatosis--a report on four cases: evidence for B phenotype of the tumoral cells

Four cases of lymphomatoid granulomatosis are reported, three of them involving the lung. Histological features included a true angiocentric and angiodestructive polymorphic cellular proliferation. This included histiocytes, plasma cells, many reactive T-cells and rare large, atypical cells which were of the B phenotype. Epstein-Barr virus was detected in the atypical cells by in situ hybridization in three cases, with expression of both latent membrane proteins (LMP)-1 and Epstein-Barr nuclear antigen-2 in two cases and expression of only LMP-1 in the third case. Expression of both of these proteins suggests a defect in the T-cell-mediated immunity and that Epstein-Barr virus is not only a silent passenger but may also be involved in the pathogenesis of the disease. This could have implications for therapy.

Pyothorax-associated lymphoma: relationship with Epstein-Barr virus, human herpes virus-8 and body cavity-based high grade lymphomas

Pyothorax-associated lymphoma (PAL) is a newly-described entity developing several decades after artificial pneumothorax treatment for pulmonary or pleural tuberculosis. It is known to be associated with Epstein-Barr virus (EBV) with constant expression of the two latent membrane proteins: latent membrane protein (LMP)-1 and EBV-associated nuclear antigen (EBNA)-2. We are reporting three new cases of PAL. All of the tumours were of B-cell lineage and classified as large-cell diffuse lymphomas according to the International Working Formulation for the Classification of Lymphomas. The EBV genome was detected in two of the cases with LMP-1 and EBNA-2 expression. No EBV could be detected in the third case suggesting that different mechanisms may be involved in the pathogenesis of the disease. Body cavity-based high grade lymphomas (BCBL) represent a new disease, developing mainly in human immunodeficiency virus (HIV) infected patients: the tumoural cells often contain both human herpes virus (HHV)-8 (or Kaposi's sarcoma herpes virus) and EBV genomes, suggesting that these viruses might co-operate in the pathogenesis of the disease. The pleural location and the association of EBV have led to speculation that PAL could also be related to HHV-8 infection. However, no HHV-8 genome could be detected in any of the 14 tested cases already reported in the literature nor in the two cases we studied (one EBV-positive and one EBV-negative), suggesting that PAL and BCBL are two different entities.

Primary hepatocellular carcinoma in workers exposed to vinyl chloride: a report of two cases

BACKGROUND

Vinyl chloride (VC), an industrial toxic gas, has a dose-dependent carcinogenicity in rodents and has been responsible for multiple cases of liver angiosarcoma in humans. The aim of this study was to describe histopathologic liver alterations and to evaluate risk factors for hepatocellular carcinoma in two workers from the same plant, both of whom had primary nonangiosarcoma liver tumors and were exposed to VC.

METHODS

Clinical, biochemical, serologic, and pathologic data were reviewed at the time of hepatic resection. Clinical and biologic follow-up were available for several years before the diagnosis of hepatocellular carcinoma.

RESULTS

Liver alterations distant from the tumor site were compatible with ongoing exposure to VC in both cases. Several areas containing dysplastic hepatocytes were present in nontumoral liver in one patient. Both patients are alive after partial liver resection, and 1 has had 5 years of follow-up without recurrence.

CONCLUSIONS

Exclusion of classic risk factors for noncirrhotic hepatocellular carcinoma of the liver in both patients suggests a relationship between VC exposure and observed tumors. Systematic long term follow-up with biology and ultrasonography for workers exposed to VC may result in relatively early diagnoses of liver tumors and long term survival in some cases.