Presence of a 34-gene signature is a favorable prognostic marker in squamous non-small cell lung carcinoma.

BACKGROUND: The tumor immune microenvironment is a heterogeneous entity. Gene expression analysis allows us to perform comprehensive immunoprofiling and may assist in dissecting the different components of the immune infiltrate. As gene expression analysis also provides information regarding tumor cells, differences in interactions between the immune system and specific tumor characteristics can also be explored. This study aims to gain further insights in the composition of the tumor immune infiltrate and to correlate these components to histology and overall survival in non-small cell lung cancer (NSCLC). METHODS: Archival tissues from 530 early stage, resected NSCLC patients with annotated tumor and patient characteristics were analyzed using the NanoString nCounter Analysis system. RESULTS: Unsupervised clustering of the samples was mainly driven by the overall level of inflammation, which was not correlated with survival in this patient set. Adenocarcinoma (AD) showed a significantly higher degree of immune infiltration compared to squamous cell carcinoma (SCC). A 34-gene signature, which did not correlate with the overall level of immune infiltration, was identified and showed an OS benefit in SCC. Strikingly, this benefit was not observed in AD. This difference in OS in SCC specifically was confirmed in two independent NSCLC cohorts. The highest correlation between expression of the 34-gene signature and specific immune cell populations was observed for NK cells, but although a plausible mechanism for NK cell intervention in tumor growth could be established in SCC over AD, this could not be translated back to immunohistochemistry, which showed that NK cell infiltration is scarce irrespective of histology. CONCLUSIONS: These findings suggest that the ability of immune cell infiltration and the interaction between tumor and immune cells may be different between AD and SCC histology and that a subgroup of SCC tumors seems more susceptible to Natural Killer cell recognition and killing, whereas this may not occur in AD tumors. A highly sensitive technique like NanoString was able to detect this subgroup based on a 34-gene signature, but further research will be needed to assist in explaining the biological rationale of such low-level expression signatures.

Leakage evaluation with and without vacuum of two gutta-percha fill techniques.

Two sets of 30 roots were obturated either with lateral condensation or a halothane dip technique. Fifteen roots from each group were immersed in India ink with vacuum and 15 without vacuum. Each root was coated with nail polish and wax, leaving only its apical end open for ink penetration. The roots were cleared and three linear measurements were made: distance of ink penetration coronal to the gutta-percha apical tip; distance from the gutta-percha tip to major foramen; and distance from the major foramen to anatomical apex. The average length of ink penetration coronal to the apical extension of the gutta-percha for the lateral condensation groups combined was 1.33 mm and for the halothane groups combined was 2.15 mm. There was no significant difference between vacuumed and not vacuumed for degree of ink penetration. The gutta-percha of the halothane-dipped groups advanced significantly closer to the foramen than the lateral condensation groups (0.38 mm versus 0.65 mm).

Radiographic evaluation of extruded obturation materials.

The radiographic appearance of filling material extruded into periradicular tissues during obturation of root canals was studied over time. Recall radiographs for up to 6 1/2 yr were compared with immediate postoperative films. Consistently, less material was evident at successive postoperative periods. This study indicated that given time, the two zinc oxide and eugenol-based sealers studied will be removed from periradicular tissues. It also indicated that sealer is removed from periradicular tissues more rapidly than gutta-percha.

Incidence and configuration of canal systems in the mesiobuccal root of maxillary first and second molars.

The anatomy of the mesiobuccal (MB) root of 51 maxillary first and 32 maxillary second molars was studied. Initially, an attempt was made to locate all canals using a standard access and hand instruments. A bur was next used carefully to locate any additional second mesiobuccal (mesiolingual (ML)) canals. Finally, after crown removal, the teeth were reduced horizontally in 1-mm increments and examined by microscope. A second ML canal was located in the coronal half of 95.2% of the roots: by hand instruments in 54.2%; bur in 31.3%; and microscope in 9.6%. There were no root perforations when the bur was used as described. The ML canal orifice averaged 1.82 mm lingual to the MB canal orifice. The difference in incidence of ML canals between the first and second molars was not statistically significant. The canal systems were type 1, 4.8%; type 2, 49.4%, and type 3, 45.8%.

Adult pulpal diagnosis. I. Evaluation of the positive and negative responses to cold and electrical pulp tests.

This study investigated the positive and negative responses of 1488 teeth in 60 patients to two electric pulp testers and a cold thermal pulp test. Three subgroups of known pulpless or pulpally diseased teeth (teeth receiving root canal therapy, teeth with root canal fillings, or teeth with confirmed associated apical radiolucencies) were identified and their responses evaluated separately. Testing was performed on two tooth surfaces, the facio-occlusal and faciocervical, and on all restorations. The gingival tissue of each patient also was tested using both electrical tests. The primary findings were: (a) teeth not responding to cold and either not responding or responding at readings greater than the tissue response to electrical had a high probability of being in the known pulpless or pulpally diseased subgroups; (b) the only false positive responses to cold in the three subgroups were in multirooted teeth with probable vital tissue remaining in at least one canal; and (c) in the three subgroups, if the false positive responses to electrical that responded at levels higher than the patient's tissue response were considered to be negative responses, the difference in false positives between cold and electrical became not statistically significant (p = 0.07).

Radiographic determination of canal length direct digital radiography versus conventional radiography.

This research compared the length determination images produced by Trophy and Regam direct digital radiographic systems with conventional E-speed radiographs. Size #15 K files were placed in the canals of 19 teeth of cadaver specimens and radiographed in a geometrically standardized bench device. Three evaluators estimated the length adjustment necessary to position the file at the apex. The mean estimated adjustment lengths were compared with the true, anatomically determined adjustment lengths. Statistical analysis with analysis of variance and the Student-Newman-Keuls test indicated no significant difference between direct digital thermal print images and conventional radiographs (p > 0.10). Length adjustment estimates with conventional radiographs were significantly more accurate than Regam high-resolution computer monitor images (p < 0.01). Additionally, it was determined that length adjustment estimates were significantly more accurate when the file was placed short of the apex (p < 0.001). The clinical relevance of these differences is discussed.

Microcomputed tomography: an advanced system for detailed endodontic research.

This study evaluated the value of microcomputed tomography (MCT) for use in endodontic research. Four periodontally involved highly calcified maxillary first molars were extracted and then scanned for evaluation by a MCT system. The teeth were then instrumented, and 2 of the 4 obturated before rescanning for comparison evaluation. Several capabilities of the MCT to advance endodontic research significantly were observed: the ability of the MCT to present accurately the external and internal morphologies of the tooth without tooth destruction; the possibility of showing changes over time in surface areas and volumes of tissues; the ability to assess area and volume changes after instrumentation or obturation; and the capability of evaluating canal transportation following instrumentation or instrumentation and obturation. The tremendous potential of this scientific tool was discussed.