Abstract: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine malignancy that is associated with a poor prognosis. The pathogenesis of MCC is not well understood, and despite a recent plethora of mutational analyses, we have yet to find a set of signature mutations implicated in the majority of cases. Mutations, including TP53, Retinoblastoma and PIK3CA, have been documented in subsets of patients. Other mechanisms are also likely at play, including infection with the Merkel cell polyomavirus in a subset of patients, dysregulated immune surveillance, epigenetic alterations, aberrant protein expression, posttranslational modifications and microRNAs. In this review, we summarize what is known about MCC genetic mutations and chromosomal abnormalities, and their clinical significance. We also examine aberrant protein function and microRNA expression, and discuss the therapeutic and prognostic implications of these findings. Multiple clinical trials designed to selectively target overexpressed oncogenes in MCC are currently underway, though most are still in early phases. As we accumulate more molecular data on MCC, we will be better able to understand its pathogenic mechanisms, develop libraries of targeted therapies, and define molecular prognostic signatures to enhance our clinicopathologic knowledge.
Abstract: Small-cell lung cancer (SCLC) is one of the most aggressive lung tumors. The majority of patients with SCLC are diagnosed at an advanced stage. This tumor type is highly sensitive to chemo-radiation treatment, with very high response rates, but invariably relapses. At this time, treatment options are still limited and the prognosis of these patients is poor. A better knowledge of the molecular biology of SCLC allowed us to identify potential druggable targets. Among these, the MET/HGF axis seems to be one of the most aberrant signaling pathways involved in SCLC invasiveness and progression. In this review, we describe briefly all recent literature on the different molecular profiling in SCLC; in particular, we discuss the specific alterations involving c-MET gene and their implications as a potential target in SCLC.
Abstract: The newly gained knowledge of the viral etiology in cervical carcinogenesis has prompted industrial interests in developing virology-based tools for cervical cancer prevention. Due to the long incubation period from viral infection to developing an invasive cancer, a process whose outcome is influenced by numerous life-style and genetic factors, the true efficacy of the genotype-specific human papillomavirus (HPV) vaccines in cervical cancer prevention cannot be determined for another 30 years. Most HPV DNA test kits designed to replace the traditional Papanicolaou (Pap) smears for precancer detection lack the analytical sensitivity and specificity to comprehensively detect all potentially carcinogenic HPVs and to perform reliable genotyping. The authors implemented the classic nested PCR and Sanger DNA-sequencing technology for routine HPV testing. The results showed a true negative HPV PCR invariably indicates the absence of precancerous cells in the cytology samples. However, 80.5% of single positive HPV-16 tests and 97.3% of single positive HPV-18 tests were associated with a negative or a largely self-reversible Pap cytology. Routine sensitive and reliable HPV type-specific or perhaps even variant-specific methods are needed to address the issues of persistence of HPV infection if a virology-based primary cervical screen is used to replace the Pap cytology screening paradigm.
Abstract: This review summarizes the mechanisms that control the activity of the c-Myb transcription factor in normal cells and tumors, and discusses how c-Myb plays a role in the regulation of the cell cycle. Oncogenic versions of c-Myb contribute to the development of leukemias and solid tumors such as adenoid cystic carcinoma, breast cancer and colon cancer. The activity and specificity of the c-Myb protein seems to be controlled through changes in protein-protein interactions, so understanding how it is regulated could lead to the development of novel therapeutic strategies.
Abstract: The activation of lymphocytes by gefitinib treatment has been described. In this phase II pilot trial, we explored the possible synergism between IL-2 and gefitinib for non-small cell lung cancer (NSCLC) treatment. From September, 2003, to November, 2006, 70 consecutive patients with advanced, progressive NSCLC, previously treated with chemotherapy, received oral gefitinib 250 mg daily. The first 39 patients received gefitinib alone (G group). The other 31 also received subcutaneous IL-2 (GIL-2 group): 1 MIU/m2 (Million International Unit/m2)twice a day on Days 1 and 2, once a day on Days 3, 4, 5 every week for four consecutive weeks with a four-week rest period. Median follow-up was 25.2 months. Grade 3–4 toxicity of gefitinib was represented by skin rash (7%), asthenia/anorexia (6%) and diarrhea (7%); patients treated with IL-2 showed grade 2–3 fever (46%), fatigue (21%) and arthralgia (13%). In the GIL-2 group and G-group, we respectively observed: an overall response rate of 16.1% (6.4% complete response) and 5.1% (only partial response); a disease control rate of 41.9% and 41%; a median time to progression of 3.5 (CI 95% = 3.2–3.8) and 4.1 (CI 95% = 2.6–5.7) months; a median overall survival of 20.1 (CI 95% = 5.1–35.1) and 6.9 (CI 95% = 4.9–8.9) months (p = 0.002); and an actuarial one-year survival rate of 54% and 30%. Skin toxicity (p < 0.001; HR = 0.29; CI 95% = 0.16–0.54) and use of IL-2 (p < 0.001; HR = 0.33; CI 95% = 0.18–0.60) were independently associated with improvement of survival. In this consecutive, non-randomized, series of advanced NSCLC patients, the use of IL-2 increased the efficacy of gefitinib.
Abstract: Since its discovery in mice and humans 19 years ago, the contribution of alternatively spliced Stat3, Stat3β, to the overall functions of Stat3 has been controversial. Tyrosine-phosphorylated (p) Stat3β homodimers are more stable, bind DNA more avidly, are less susceptible to dephosphorylation, and exhibit distinct intracellular dynamics, most notably markedly prolonged nuclear retention, compared to pStat3α homodimers. Overexpression of one or the other isoform in cell lines demonstrated that Stat3β acted as a dominant-negative of Stat3α in transformation assays; however, studies with mouse strains deficient in one or the other isoform indicated distinct contributions of Stat3 isoforms to inflammation. Current immunological reagents cannot differentiate Stat3β proteins derived from alternative splicing vs. proteolytic cleavage of Stat3α. We developed monoclonal antibodies that recognize the 7 C-terminal amino acids unique to Stat3β (CT7) and do not cross-react with Stat3α. Immunoblotting studies revealed that levels of Stat3β protein, but not Stat3α, in breast cancer cell lines positively correlated with overall pStat3 levels, suggesting that Stat3β may contribute to constitutive Stat3 activation in this tumor system. The ability to unambiguously discriminate splice alternative Stat3β from proteolytic Stat3β and Stat3α will provide new insights into the contribution of Stat3β vs. Stat3α to oncogenesis, as well as other biological and pathological processes.