Molecular and cytogenetic subgroups of oropharyngeal squamous cell carcinoma.

PURPOSE: The aim of this study was to acquire further insights into the pathogenetic pathways of head and neck squamous cell carcinomas (HNSCC) that may be useful for identifying new biomarkers instrumental in developing more specific treatment approaches. EXPERIMENTAL DESIGN: Cell cycle regulators and epidermal growth factor receptor (EGFR) and BRAF genes were analyzed in a series of 90 oropharyngeal SCCs of a cohort of surgically treated patients from a single institution, and the results were matched with the presence of high-risk human papillomavirus (HR-HPV) DNA and the TP53 status. RESULTS: At least four distinct groups of tumors were identified sharing a common histology but displaying different molecular/cytogenetic patterns: (a) 19% were HPV-positive SCCs whose lack of alterations of the investigated genes could explain their particular natural history, which requires less aggressive treatment; (b) 37% were HPV-negative SCCs carrying TP53 mutations, which may be more effectively treated by drugs acting through p53-independent apoptosis; (c) 34% were HPV-negative SCCs carrying wild-type TP53 and loss of 9p21 (p16INK4a and p15INK4b) and/or cyclin D1 overexpression that justify treatment with DNA-damaging drugs followed by cell cycle inhibitors; and (d) 10% were HPV-negative lacking tumor suppressor genes and cell cycle alterations. The second, third, and fourth groups also showed an increased copy number of EGFR and chromosome 7 (43%) that might justify the additional or alternative use of EGFR inhibitors. CONCLUSIONS: Our findings suggest that assessing HPV, TP53, 9p21, and EGFR status may be crucial to finding more tailored and beneficial treatments for oropharyngeal SCCs.

Low-dose tenofovir is more potent than adefovir and is effective in controlling HBV viremia in chronic HBeAg-negative hepatitis B.

AIM: To study the efficacy of tenofovir disoproxil fumarate (TDF) at low dose in a small open trial of chronic hepatitis B patients with advanced stage disease. METHODS: Eleven patients were treated with TDF 75 mg for a median period of 80 (range, 24-576) wk and then 7 cases were shifted to an adefovir 10 mg treatment group. All patients had been pre-treated with lamivudine: 5 had YMDD resistant mutants and 6 wild-type virus. When TDF was started, 4 patients had low-level viremia and 6 were PCR-negative. RESULTS: During TDF treatment, PCR remained negative in 10 patients, transaminase levels were normal and no significant viral breakthrough was observed. The drug was well tolerated in all cases. When TDF 75 mg was substituted with adefovir 10 mg, 3 out of 7 patients had a persistent viral rebound (2700-130,000 copies/mL), in whom lamivudine had to be reintroduced. CONCLUSION: Low-dose TDF monotherapy can control HBV viremia for an extended period of time without the emergence of resistance and is more potent than adefovir at the standard dosage. The use of a reduced dose of TDF could diminish the cost of therapy in low-income countries, but further studies in a larger population and in HBeAg-positive subjects are needed.

Long-term results of conventional radiotherapy versus accelerated hyperfractionated radiotherapy versus concomitant radiotherapy and chemotherapy in locoregionally advanced carcinoma of the oropharynx.

AIMS AND BACKGROUND: To compare conventional fractionation (CF) radiation therapy (RT), arm A, versus a split-course accelerated hyperfractionated schedule (S-AHF), arm B, versus CFRT plus concomitant chemotherapy (CT), arm C, in terms of five-year survival and toxicity for squamous cell tumors of the oropharynx. METHODS AND STUDY DESIGN: Between January 1993 and June 1998, 192 previously untreated patients with stage III and IV oropharyngeal carcinoma (excluding T1N1 and T2N1) were enrolled in a multicenter randomized phase III trial (ORO 93-01). In arms A and C, 66 to 70 Gy in 33 to 35 fractions was administered five days a week for six and a half to seven weeks. In arm B, the dose delivered was 64 to 67.2 Gy in two fractions of 1.6 Gy every day, five days a week, with a planned two-week split at 38.4 Gy. In arm C the CT regimen consisted of three cycles of carboplatin and 5-fluorouracil (CBDCA 75 mg/m2 on days 1 to 4 and 5-FU 1000 mg/m2 i.v. on days 1 to 4 every 28 days). RESULTS: No statistically significant difference was found in five-year overall survival (P = 0.39): 21% for arm A, 21% for arm B, and 40% for arm C. Similarly, there was no statistically significant difference in terms of five-year relapse-free survival: 15% for arm A, 17% for arm B, and 36% for arm C. There was a slight trend towards better five-year locoregional control (P = 0.07) for the combined arm: patients without locoregional relapse were 48% in arm C, 21% in arm A and 18% in arm B. Locoregional control was significantly better when arm C was compared with arms A and B combined (P = 0.02; arm A+B 20%; arm C 48%). Distant metastases were fairly balanced in the three arms (A: 14; B: 9; C: 11), with a tendency towards more frequent isolated distant metastasis development in arm C (8 of 11 [72%] versus 7 of 23 [30%] in arms A+B). Five-year second-tumor-free survival was 85%. The 13 second tumors were equally distributed and were mainly correlated with tobacco and alcohol consumption (five lung, two esophagus, two oral cavity, one larynx, one pancreas, one hepatocarcinoma, one myeloma). Arm C showed slightly more G3+ late side effects involving subcutaneous tissues and mucosa, although significant late sequelae were relatively uncommon and the mucosal side effects were mostly transient. The occurrence of persistent G3 xerostomia was comparable in the three treatment arms. CONCLUSIONS: The results obtained with the combination of CT and RT compared with RT alone did not reach statistical significance, but combined treatment almost doubled the five-year overall survival, relapse-free survival and locoregional control rate. Patients with advanced squamous cell carcinomas of the oropharynx who are medically suitable for the combined approach should be treated with a combination of radiotherapy and chemotherapy. The occurrence of second tumors is relatively common in these patients and may contribute substantially to the causes of death.

BRAF alterations are associated with complex mutational profiles in malignant melanoma.

To evaluate the mutational profiles associated with BRAF mutations in human melanoma, we have studied BRAF, RAS, PTEN, TP53, CDKN2A and CDK4 genes and their expression in melanoma lesions. Owing to the lack of sufficient material from fresh specimens, we employed short-term cell lines obtained from melanoma biopsies. In all, 41 melanoma obtained from eight primary lesions, 20 nodal, 11 cutaneous and two visceral metastases from patients with sporadic (n=31), familial (n=4) and multiple melanoma (n=2) were analysed. The results revealed novel missense mutations in the BRAF, PTEN, CDKN2A and CDK4 genes. Overall, activating mutations of BRAF and loss of functional p16 and ARF were detected in the majority of melanomas (29/41, 36/41 and 29/41, respectively), while PTEN alterations/loss, NRAS and TP53 mutations occurred less frequently (6/41, 6/41 and 10/41, respectively). In the resulting 12 mutational profiles, p16/ARF loss associated with mutated BRAFV599E was the most represented (n=15). In addition, TP53 and PTEN mutations were always accompanied with BRAF alterations, while PTEN loss was found in association with CDKN2A or TP53 mutations in the absence of BRAF activation. The p16/ARFDelta+BRAF/RAS profile was significantly associated with a longer survival, while complex mutational profiles were detected in highly aggressive disease and poor survival. These data support the existence of several molecularly defined melanoma groups which likely reflect different clinical/biological behaviour, thus suggesting that a more extensive molecular classification of melanoma would significantly impact its clinical management.

Gene expression profiling of advanced ovarian cancer: characterization of a molecular signature involving fibroblast growth factor 2.

Epithelial ovarian cancer (EOC) is the gynecological disease with the highest death rate. We applied an automatic class discovery procedure based on gene expression profiling to stages III-IV tumors to search for molecular signatures associated with the biological properties and progression of EOC. Using a complementary DNA microarray containing 4451 cancer-related, sequence-verified features, we identified a subset of EOC characterized by the expression of numerous genes related to the extracellular matrix (ECM) and its remodeling, along with elements of the fibroblast growth factor 2 (FGF2) signaling pathway. A total of 10 genes were validated by quantitative real-time polymerase chain reaction, and coexpression of FGF2 and fibroblast growth factor receptor 4 in tumor cells was revealed by immunohistochemistry, confirming the reliability of gene expression by cDNA microarray. Since the functional relationships among these genes clearly suggested involvement of the identified molecular signature in processes related to epithelial-stromal interactions and/or epithelial-mesenchymal cellular plasticity, we applied supervised learning analysis on ovarian-derived cell lines showing distinct cellular phenotypes in culture. This procedure enabled construction of a gene classifier able to discriminate mesenchymal-like from epithelial-like cells. Genes overexpressed in mesenchymal-like cells proved to match the FGF2 signaling and ECM molecular signature, as identified by unsupervised class discovery on advanced tumor samples. In vitro functional analysis of the cell plasticity classifier was carried out using two isogenic and immortalized cell lines derived from ovarian surface epithelium and displaying mesenchymal and epithelial morphology, respectively. The results indicated the autocrine, but not intracrine stimulation of mesenchymal conversion and cohort/scatter migration of cells by FGF2, suggesting a central role for FGF2 signaling in the maintenance of cellular plasticity of ovary-derived cells throughout the carcinogenesis process. These findings raise mechanistic hypotheses on EOC pathogenesis and progression that might provide a rational underpinning for new therapeutic modalities.

Type-specific multiple sequencing primers: a novel strategy for reliable and rapid genotyping of human papillomaviruses by pyrosequencing technology.

DNA sequencing is the gold standard method for accurate microbial and viral typing. However, DNA sequencing techniques have been facing limitations in typing of human papillomaviruses when the specimen harbors multiple genotypes and yields nonspecific amplification products, resulting in nonspecific and noninterpretable sequence data. To address these limitations we have developed a type-specific multiple sequencing primer DNA-sequencing method. This new strategy is suitable for sequencing and typing of samples harboring different genotypes (co-infections with multiple genotypes) and yielding nonspecific amplifications, thus eliminating the need for nested polymerase chain reaction (PCR), stringent PCR conditions, and cloning. The new approach has also proved useful for amplicons containing low PCR yield or subdominant types, avoiding reperforming of amplifications. We have applied the multiple sequencing primer method for genotyping of clinically relevant human papillomaviruses in a clinical test panel by using a combined pool of seven type-specific sequencing primers for HPV-6, -11, -16, -18, -31, -33, and -45. Furthermore, we introduced a sequence pattern recognition approach when there was a plurality of genotypes in the sample to facilitate typing of more than one target DNA in the sample. The multiple sequencing primer method has proved to be a multifaceted approach for typing of human papillomaviruses by DNA sequencing technologies.

Different genetic features associated with colon and rectal carcinogenesis.

PURPOSE: The issue of whether colon and rectal cancer should be considered as a single entity or two distinct entities is still debated, and there is a need to improve studies addressing the heterogeneity of the pathogenetic pathway leading to sporadic colorectal cancers (SCRCs) as well as to identify biological and/or molecular differences between colon and rectal cancers. EXPERIMENTAL DESIGN: Specimens of SCRCs were analyzed for somatic mutations in APC, K-ras, and TP53 genes and loss-of-heterozygosity of chromosome 18. RESULTS: Eleven SCRCs showed microsatellite instability. APC mutation frequency was significantly lower in microsatellite instability (MIN+) than in MIN- SCRCs. All MIN- SCRCs showed beta-catenin overexpression. A combined analysis of the biomarkers revealed two pathways mainly represented by MIN- SCRCs and differently followed on the basis of tumor location, APC-K-ras-TP53-Ch18q and APC-TP53-Ch18q. CONCLUSIONS: The APC-beta-catenin pathway is inactivated in MIN- SCRCs and represents the first hit of SCRC development. Two preferential pathways followed by SCRCs occur, one K-ras dependent, in agreement with the Fearon and Vogelstein model, and the other K-ras independent. Significant differences between colon and rectal tumors occur in our series of MIN- SCRCs. The different pathways observed and their distribution can be summarized as follows: (a) K-ras mutations were more commonly detected in colon than in rectum; (b) the number of mutations detected was significantly higher in colon than in rectal tumors; and (c) a mutational pattern restricted to the APC gene was more common in rectal than in colon tumors. This molecular characterization can be translated into a clinical setting to improve diagnosis and to direct a rationale pharmacological treatment.

CD95-mediated apoptosis is impaired at receptor level by cellular FLICE-inhibitory protein (long form) in wild-type p53 human ovarian carcinoma.

PURPOSE: Ovarian carcinoma is a highly lethal malignancy that often becomes resistant to chemotherapy. Alterations in apoptotic signals and p53 status contribute to drug resistance, and CD95-mediated apoptosis is also deficient in resistant cells. We analyzed the mechanism of resistance to CD95-mediated apoptosis in ovarian carcinoma cell lines differing in p53 status. EXPERIMENTAL DESIGN: CD95-mediated apoptosis was induced by agonistic anti-CD95 antibody, and the apoptotic cascade was monitored with biochemical and functional assays. RESULTS: CD95-mediated apoptosis was blocked in human ovarian cancer cells. In cell lines with wild-type p53, treatment with the protein synthesis inhibitor cycloheximide (CHX) together with anti-CD95 overcame the resistance, suggesting the presence of a labile inhibiting protein. Indeed, the labile protein cellular FLICE-inhibitory protein long form (c-FLIP(L)) was found to block caspase-8 recruitment to the death-inducing signaling complex (DISC), and sensitization of cells by CHX was due to c-FLIP(L) down-modulation at the DISC level. Down-regulation of c-FLIP(L) with antisense oligonucleotides increased CD95-mediated apoptosis as in cells sensitized by CHX, demonstrating the direct involvement of c-FLIP(L) in apoptosis resistance. Removal of c-FLIP(L) block at DISC level allowed full activation of the mitochondrial pathway and, eventually, apoptosis in wild-type p53 cells, whereas in cells with mutated p53, c-FLIP(L) involvement in CD95-mediated apoptosis resistance appeared to be irrelevant. Immunohistochemical analysis of an ovarian tumor tissue array revealed c-FLIP(L) expression in samples with no p53 accumulation (P = 0.034), and a significant (P = 0.037) inverse relationship between c-FLIP(L) and p53 expression levels was also observed in 27 epithelial ovarian cancer specimens with known p53 status. CONCLUSION: The inhibitory protein c-FLIP(L) is involved in resistance to CD95-mediated apoptosis in ovarian carcinoma cells with wild-type p53.

Molecular changes track recurrence and progression of bronchial precancerous lesions.

Diagnosis of lung cancer is reached when the disease had grown to advanced stages in its natural history. Thus, novel molecular markers for early detection and risk assessment are needed. Here we performed a longitudinal study of 20 morphological lesions occurred in the bronchial tree of high-risk patients. The lesions were subjected to LIFE (laser-induced fluorescence endoscopy) bronchoscopy and molecular follow-up over a 4 year period. The presence and the persistence of specific genetic alterations were correlated with recurrence or progression of the disease on follow-up. Molecular lesions considered as highly predictive of invasion could be prospectively used as diagnostic markers of high risk for lung cancer in exposed patients.

High-risk human papillomavirus affects prognosis in patients with surgically treated oropharyngeal squamous cell carcinoma.

PURPOSE: Human papillomavirus (HPV) DNA tumors actively integrating the E6 and E7 oncogenes have a distinct biologic behavior resulting in a more favorable prognosis. To which extent the viral integration by itself, and/or the associated wild-type (wt) TP53 status, and/or a functional p16 contribute to prognosis is unclear. PATIENTS AND METHODS: To clarify how the presence of high-risk (HR) -HPV, TP53, and p16INK4a status interact with clinical outcome, we considered a retrospective series of 90 consecutive oropharyngeal cancer patients treated primarily with surgery. RESULTS: Seventeen (19%) patients showed integrated HPV 16 DNA (HPV positive), wt TP53 in all but two patients, normal p16INK4a in 15 assessable patients, and p16 expression in all 17 patients. Thirty-five patients (39%), two of whom were HPV positive, harbored TP53 mutations. p16INK4a deletion and p16 null immunophenotype occurred in 28 and 58 patients, respectively, and was similarly distributed in both patients with mutated TP53 (48% and 82%, respectively) and in patients with wt TP53 (46% and 77%, respectively). Statistical analysis showed that HPV-positive status significantly affects all investigated end points: overall survival (P = .0018), incidence of tumor relapse (P = .0371), and second tumor (P = .0152), whereas TP53 and p16INK4a status and p16 expression were not prognostic by themselves. CONCLUSION: Our molecular and clinical results are in agreement with previous findings but provide additional information into the biologic mechanisms involved in HR-HPV oropharyngeal cancer in comparison to HPV-negative tumors. According to the reduced risk of relapse and second tumors associated with HR-HPV positivity of oropharyngeal cancer, the therapeutic strategy and follow-up procedures should be reviewed.

TP53, p14ARF, p16INK4a and H-ras gene molecular analysis in intestinal-type adenocarcinoma of the nasal cavity and paranasal sinuses.

Intestinal-type adenocarcinoma (ITAC) of the nasal cavity and paranasal sinuses is an uncommon tumor associated with occupational exposure to dusts of different origin. Few investigations addressed molecular alterations in ITAC mainly focused on TP53, K-ras and H-ras gene mutations. The occurrence of TP53, p14(ARF) and p16(INK4a) deregulation and H-ras mutations was investigated in 21 consecutive and untreated ITACs cases, 17 with known professional exposure. No H-ras mutations were found. In patients with known exposure, cumulative evidence of TP53 or p14(ARF) alterations accounted for 88% and the evidence of p16(INK4a) alterations for 65%, respectively. TP53 mutations were present in 44% of the ITACs, consisted of G:C-->A:T transitions in 86%, and involved the CpG dinucleotides in 50% of the cases. LOH at the locus 17p13 and an uncommon high rate of p53 stabilization were detected in 58% and 59% of the cases, respectively. p14(ARF)and p16(INK4a) promoter methylation accounted for 80% and 67% respectively, and LOH at the locus 9p21 occurred in 45% of the cases. Interestingly, all dust-exposed tumors with p16(INK4a) alterations shared TP53 or p14(ARF) deregulation. The present results show a close association of this occupational tumor with TP53, p14(ARF) and p16(INK4a) gene deregulation. Given the important role that these genes play in cell growth control and apoptosis, the knowledge of ITAC genetic profile may be helpful in selecting more tailored treatments.