Ascl3 transcription factor marks a distinct progenitor lineage for non-neuronal support cells in the olfactory epithelium.

The olfactory epithelium (OE) is composed of olfactory sensory neurons (OSNs), sustentacular supporting cells, and several types of non-neuronal cells. Stem and progenitor cells are located basally, and are the source of all cell types needed to maintain OE homeostasis. Here, we report that Ascl3, a basic helix-loop-helix transcription factor, is expressed in the developing OE. Lineage tracing experiments demonstrate that the non-neuronal microvillar cells and Bowman's glands are exclusively derived from Ascl3+ progenitor cells in the OE during development. Following chemically-induced injury, Ascl3 expression is activated in a subset of horizontal basal cells (HBCs), which repopulate all microvillar cells and Bowman's glands during OE regeneration. After ablation of Ascl3-expressing cells, the OE can regenerate, but lacks the non-neuronal microvillar and Bowman's gland support cells. These results demonstrate that Ascl3 marks progenitors that are lineage-committed strictly to microvillar cells and Bowman's glands, and highlight the requirement for these cell types to support OE homeostasis.

Comparative analysis of temozolomide (TMZ) versus 1,3-bis (2-chloroethyl)-1 nitrosourea (BCNU) in newly diagnosed glioblastoma multiforme (GBM) patients.

PURPOSE: Although TMZ replaced BCNU as the standard initial chemotherapy in the treatment of GBM, no studies have been reported comparing BCNU with TMZ. We therefore did a retrospective analysis comparing these agents as initial therapy in GBM. PATIENTS AND METHODS: Eighty-one patients with GBM in our institution received both radiation and chemotherapy as initial treatment after surgery or biopsy; 49 receiving BCNU and 32 TMZ. These were analyzed for overall survival (OS) and progression-free survival (PFS) versus the type of chemotherapy used. The influence of salvage therapy on the outcome was investigated also. RESULTS: Median OS was superior in the TMZ versus the BCNU group (15.9 vs. 11.5 months) and the curves were judged to be significantly different by the log-rank test; P < 0.02. However, PFS was not significantly different between the two groups. Bevacizumab plus irinotecan (BI) was used as salvage therapy in one-third of the TMZ patients but in none of the BCNU patients. When patients receiving BI were omitted from the TMZ group the OS curve overlapped that of BCNU patients. CONCLUSION: These data suggest that the superior OS of the TMZ-treated GBM patients was not due to better tumor control by TMZ but was possibly related to the newer salvage therapy that was available to them.

Can positron emission tomography be used as a staging tool for small-cell lung cancer?

PURPOSE: Positron emission tomography (PET) is widely used for the staging evaluation of non-small-cell lung cancer; however, its use in small-cell lung cancer (SCLC) remains investigational. PATIENTS AND METHODS: We did a retrospective study of 137 patients to evaluate the role of PET in SCLC. Fifty-one of 137 patients had computed tomography (CT) and PET scans during initial evaluation of a lung mass. RESULTS: All 51 patients had PET-positive results for malignancy (100% sensitivity). In 40 of 51 cases (78%), the PET staging correlated with that on CT. Two of 51 patients (4%) had disease that was accurately upstaged by PET. Positron emission tomography accurately downstaged disease in 6 of 51 patients (12%). Positron emission tomography detected additional sites of disease in 13 of 42 patients (32%). Of the 13 additional sites of disease, PET detected supraclavicular nodes in 4 of 13 patients (30%) and bone lesions in 4 of 13 patients (30%). The sensitivity to detect brain lesions was 5 of 11 patients (45%) in this series. In this series, the PET results from 8 of 51 patients (16%) resulted in a change in disease management. Because of PET results, 6 of 51 patients (12%) who otherwise would not have been treated, were treated with radiation. CONCLUSION: Positron emission tomography is potentially useful for accurate initial staging of SCLC and can ensure that a patient's disease is not overstaged by CT scan, which might result in denied potentially curative treatment for limited-stage SCLC. It can identify the occult adrenal metastasis and metastasis to supraclavicular lymph nodes that are missed by CT; however, brain lesions are difficult to assess by PET.