Plasma ctDNA RAS mutation analysis for the diagnosis and treatment monitoring of metastatic colorectal cancer patients.

BACKGROUND: RAS assessment is mandatory for therapy decision in metastatic colorectal cancer (mCRC) patients. This determination is based on tumor tissue, however, genotyping of circulating tumor (ct)DNA offers clear advantages as a minimally invasive method that represents tumor heterogeneity. Our study aims to evaluate the use of ctDNA as an alternative for determining baseline RAS status and subsequent monitoring of RAS mutations during therapy as a component of routine clinical practice. PATIENTS AND METHODS: RAS mutational status in plasma was evaluated in mCRC patients by OncoBEAM™ RAS CRC assay. Concordance of results in plasma and tissue was retrospectively evaluated. RAS mutations were also prospectively monitored in longitudinal plasma samples from selected patients. RESULTS: Analysis of RAS in tissue and plasma samples from 115 mCRC patients showed a 93% overall agreement. Plasma/tissue RAS discrepancies were mainly explained by spatial and temporal tumor heterogeneity. Analysis of clinico-pathological features showed that the site of metastasis (i.e. peritoneal, lung), the histology of the tumor (i.e. mucinous) and administration of treatment previous to blood collection negatively impacted the detection of RAS in ctDNA. In patients with baseline mutant RAS tumors treated with chemotherapy/antiangiogenic, longitudinal analysis of RAS ctDNA mirrored response to treatment, being an early predictor of response. In patients RAS wt, longitudinal monitoring of RAS ctDNA revealed that OncoBEAM was useful to detect emergence of RAS mutations during anti-EGFR treatment. CONCLUSION: The high overall agreement in RAS mutational assessment between plasma and tissue supports blood-based testing with OncoBEAM™ as a viable alternative for genotyping RAS of mCRC patients in routine clinical practice. Our study describes practical clinico-pathological specifications to optimize RAS ctDNA determination. Moreover, OncoBEAM™ is useful to monitor RAS in patients undergoing systemic therapy to detect resistance and evaluate the efficacy of particular treatments.

Concordance of blood- and tumor-based detection of RAS mutations to guide anti-EGFR therapy in metastatic colorectal cancer.

BACKGROUND: Circulating tumor DNA (ctDNA) is a potential source for tumor genome analysis. We explored the concordance between the mutational status of RAS in tumor tissue and ctDNA in metastatic colorectal cancer (mCRC) patients to establish eligibility for anti-epidermal growth factor receptor (EGFR) therapy. PATIENTS AND METHODS: A prospective-retrospective cohort study was carried out. Tumor tissue from 146 mCRC patients was tested for RAS status with standard of care (SoC) PCR techniques, and Digital PCR (BEAMing) was used both in plasma and tumor tissue. RESULTS: ctDNA BEAMing RAS testing showed 89.7% agreement with SoC (Kappa index 0.80; 95% CI 0.71 - 0.90) and BEAMing in tissue showed 90.9% agreement with SoC (Kappa index 0.83; 95% CI 0.74 - 0.92). Fifteen cases (10.3%) showed discordant tissue-plasma results. ctDNA analysis identified nine cases of low frequency RAS mutations that were not detected in tissue, possibly due to technical sensitivity or heterogeneity. In six cases, RAS mutations were not detected in plasma, potentially explained by low tumor burden or ctDNA shedding. Prediction of treatment benefit in patients receiving anti-EGFR plus irinotecan in second- or third-line was equivalent if tested with SoC PCR and ctDNA. Forty-eight percent of the patients showed mutant allele fractions in plasma below 1%. CONCLUSIONS: Plasma RAS determination showed high overall agreement and captured a mCRC population responsive to anti-EGFR therapy with the same predictive level as SoC tissue testing. The feasibility and practicality of ctDNA analysis may translate into an alternative tool for anti-EGFR treatment selection.

Solitary fibrous tumour of the pleura.

Solitary fibrous tumour (SFT) of the pleura is a rare, usually benign primary tumour of the pleura. Spectrum of presentation can vary from an incidental finding on chest radiograph done for some other purpose, features of compression of surrounding structures to symptoms resulting from the tumour per se. We report a case of a female who presented with complaints of cough and chest pain in whom a diagnosis of SFT was confirmed on tru-cut biopsy and immunohistochemistry studies. The patient underwent thoracotomy and successful removal of the tumour.

Chemopreventive activity of a C-glucuronide analog of N-(4-hydroxyphenyl) retinamide-O-glucuronide against mammary tumor development and growth.

The long term chemopreventive effects of the N-(4-hydroxyphenyl) retinamide-O-glucuronide (4-HPROG), and its stable C-linked benzyl glucuronide analog, retinamidobenzyl glucuronide (4-HPRCG) on the growth and development of 7,12-dimethylbenz[a]anthracene-induced mammary tumors were compared. The retinamidobenzyl glucuronide is stable toward acid hydrolysis and resists the actions of beta-glucuronidase. The results indicate that the C-linked glucuronide analog, 4-HPRCG has a greater chemopreventive potency than an equimolar concentration of 4-HPROG. Tumor latency was 15% longer in rats fed 2 mmol/kg diet of 4-HPRCG as compared to 4-HPROG. At 80 days post DMBA-intubation, tumor incidence was 57% and 27% in the 4-HPROG and 4-HPRCG treated rats, respectively. Tumor multiplicity was also markedly decreased in the 4-HPRCG treated rats. At 80 days post DMBA intubation the control rats had an average of 1.43 tumors/rat compared to 0.71 and 0.36 tumors/rat in the 4-HPROG and 4-HPRCG respectively. The higher potency and low toxicity of 4-HPRCG suggest that this stable analog may have an in vivo chemopreventive advantage over its analog, 4-HPROG. The results also demonstrated that these glucuronide analogs do not bind effectively in vitro either to the nuclear retinoid receptors or to the cellular retinoid binding proteins. Regardless of the mode of action of these retinoids, they are clearly effective chemopreventive agents.

Myxoid leiomyoma of tunica vaginalis testis.

Myxoid leiomyoma is an extremely rare tumor, presenting as a scrotal mass. We report a case of 60 years male, who presented with a painless scrotal mass and operated as secondary hydrocoele. This lesion should be differentiated from other myxoid tumors and tumors with myxoid degeneration.

Clinical and radiological examination of root surface caries. An in vitro study.

The better knowledge of prevention and treatment of periodontal diseases is expected to give rise to retention of more number of teeth in future. However, the periodontal surgery and also the intensive mechanical oral hygiene may expose the root surfaces to cariogenic environment. The present study was intended to evaluate and compare the clinical and radiological examination of root surface caries on extracted teeth. One hundred and twenty extracted teeth, both anteriors and posteriors, collected from the Department of Oral Surgery, Pb. Govt. Dental College & Hospital, Amritsar, were examined clinically as well as radiographically from all the four surfaces. Mesial surfaces were found to be more susceptible to caries and the lingual surfaces the least. Approximately eighty percent agreement was observed in clinical and radiological examination. Thorough probing is suggested especially on buccal and lingual surfaces since radiographs of these surfaces may be difficult in vivo. It was concluded from the study that early detection of root caries is of paramount importance; and the preventive technique should be considered for elderly patients even if there is not detectable root caries.

Overhanging interproximal silver amalgam restorations. Prevalence and side-effects.

This study was undertaken to find out the prevalence of overhanging Cl. II silver amalgam restorations amongst patients visiting Pb. Govt. Dental College and Hospital, Amritsar and Govt. Dental College Hospital, Patiala. Two parameters viz. the pocket depth and the extent of bone loss were evaluated to study the after effects of the overhanging restorations. The findings of this investigation showed the alarming prevalence of overhanging restorations (64.12%) and clearly indicate the relationship of overhangs with periodontal diseases. Periodontal breakdown was more evident along with overhanging restorations as compared to unrestored contralateral teeth. The mean pocket depth in restored surfaces was 3.75 mm as compared to 3.46 mm in unrestored ones, showing 8.38% increase. The mean extent of bone loss in restored tooth surface was 1.64 mm as compared to 1.50 mm in unrestored ones, showing an increase of 9.33%.

Resinifying therapy in endodontics. A clinical and radiological evaluation.

Twenty one posterior teeth were selected at random from patients visiting outpatient Department of Punjab Govt. Dental College and Hospital, Amritsar. Out of twenty one treated teeth, seventeen had definite radiolucent area at periapex, three were non vital with no periapical radiolucent area and one tooth was vital with pulp exposure. All the teeth were treated with resinifying therapy. The treated teeth were examined after 3 months, 6 months and 9 months as regards pain on percussion, swelling and/or sinus formation. The teeth were radiographed on each follow up and the decrease/increase in radiolucency at the periapex were noted. Clinically all the treated teeth responded normal except for one which showed sinus formation after three months period of observation. This tooth was, however, retreated. Radiologically, the success rate after 9 months of observations was 84.1%. However, mean decrease in radiolucency was 2.1 mm after 3 months, 4.0 after 6 months and 5.8 after 9 months. Resinifying therapy is strongly advocated for posterior teeth with large periapical areas and also for vital teeth with pulp exposure where root canal therapy can be completed in single visit. Furthermore, the mechanism, indications and contraindication of this therapy are also discussed.

Mandibular premolars: aberrations in pulp space morphology.

One hundred and twelve mandibular first premolars and ninety six mandibular second premolars were studied to evaluate morphological aberrations in their pulp spaces. Each tooth was radiographed from two direct ions viz. buccolingual and mesiodistal and was sectioned at three sites, cementoenamel junction, middle third and apical third. 29.5%, mandibular first premolar & 13.5% mandibular second premolar exhibited second root canal with 44.60% & 46.9% curvatures respectively. Oval shape of the canal was most prevalent at cervical third area while the canal became round at middle and apical third areas. Approximately 10% mandibular first premolar exhibited C-shaped canal, while this shape was not observed in mandibular second premolar. It is concluded from this study that the knowledge of possible aberrations always help dentist realize and manage the root canal system in a better way.

Efficacy of various eugenol and non-eugenol root canal sealers in the treatment of teeth with periapical radiolucent area--a clinical and radiological study.

A clinical and radiological study was conducted to compare the efficacy of various eugenol containing Viz. Zinc oxide eugenol, CRCS and Rosen's Cement and non eugenol containing sealers and N2 on forty eight non-vital anterior teeth, with a periapical radiolucent area of 1-7mm in diameter. The patients were recalled after 30,90,150 and 210 days On radiological examination after 210 days CRCS showed maximum decrease in periapical radiolucency from 4.39 mm. to 1.80mm. The teeth treated with N2 as root canal sealer showed minimum decrease in the periapical radiolucency from 3.0 mm. to 2.15mm. On clinical examination the results were 100% successful in both the eugenol and non-eugenol groups. The radiological findings indicate that the eugenol containing are better as compared to non-eugenol containing root canal sealer. Out of eugenol containing root canal sealers CRCS showed maximum decrease in radiolucency and from non-eugenol containing group N2.

Study of root canals and their configuration in maxillary second permanent molar.

The present in-vitro study was undertaken to know root canals and their configuration (type, curvature, number of apical foramen etc) in maxillary second permanent molar. Separately, fifty teeth by radiographic method and by decalcification method were studied. Radiologically in mesiobuccal root, two root canals were found in 78% and 20% of the specimens in mesiodistal and buccolingual direction respectively. In the distobuccal root, 2 root canals were seen in 4% and 6% of the specimen in mesiodistal and buccolingual direction respectively. Two root canals also varied in both radiological as well as decalcification methods. It is concluded from the present study that mesiobuccal roots of maxillary second molar exhibited anatomical variations and aberrant findings in the root canals. More care should always be exercised to locate the extra canal in these roots.

Resinifying therapy in endodontics. II--Histological and bacteriological evaluation.

This study was conducted on six rabbits, six rats and six human permanent teeth to evaluate histologically the effect of resin resorcinol in the periapical areas, the bacteriological aspect of the resin and the penetration of resin in the dentinal tubules. After 12 days period of observation plenty of lymphocytes and macrophages were evident along with granulomas which are suggestive of the tendency of the resin to stay longer. It was observed that the resin penetrate approximately three fourth distance inside the dentinal tubules. In the last phase the resin was found to be effective against the eight commonly found micro organisms. Though the histological results indicated that the periapical tissue would take longer time for complete repair, yet clinically the tooth functions well. Resinifying therapy is effective and economical method in root canal treatment.

Evaluation of decalcified allogenic bone matrix grafts in and around root apices. A histological study.

Decalcified Allogenic Bone grafts were implanted in and around eighteen root apices after apicoectomy. The procedure was carried out on eighteen rabbits, dividing them into three groups of six rabbits each. The animals were sacrificed after 48-72 hours, 8-10 days & 8-10 weeks period of interval. Result of the present investigation reveal that DABM grafts stimulate osteogenesis and cementogenesis after the initial phase of inflammation. Tissues simulating bone and cementum appear at the apical end, speculating that the grafts would certainly result in physiological sealing of root apices. The possibility of saving the life of non vital teeth with or without wide apical foramen will enhance in future.

Attainment of hermetic seal with decalcified allogenic bone matrix grafts--surgical vs. conservative approach.

Twenty four non vital upper anterior teeth from twelve healthy patients, between the ages of 18-30 years, having definite radiolucent areas at the periapex, were taken for this study. A comparison was made between the surgical and conservative approach, using decalcified allogenic bone matrix (DABM) grafts to achieve a physiologic seal at the root apex. The period of observation were 60 days, 120 days and 180 days. The clinical and radiological finding of this study strongly support the observation that DABM accelerates osteogenesis and cementogenesis which seal the root apex through a physiological process. The process of healing was quicker when the surgical approach was used. However a longer period of observation and histological study is required before any conclusion can be drawn, as regard the choice of a surgical or conservative approach.