Revolutionizing Dental Implant Research: A Systematic Review on Three-Dimensional In Vitro Models.

Dental implants have been clinically used for almost five decades with high success rates. In vitro research models used in implant dentistry are limited to two-dimensional experiments, which are reproducible and well adapted to evaluate a single parameter but do not reproduce the complexity of clinical settings. On the contrary, the in vivo research models using animals offer similar histological and anatomical features to humans, and tissue healing can be close to a clinical situation, but those models are usually accompanied with ethical concerns, and their outcomes could not be extrapolated to humans because of interspecies variabilities. This makes the development of novel in vitro models that recapitulate physiological events occurring during dental implant placement of particular interest for current research in dentistry. Also, such models could be challenged by setting a pathological environment (peri-implantitis) to better understand the disease and eventually serve as a platform to evaluate novel treatment modalities. The aim of this systematic literature review was to cover all the in vitro three-dimensional (3D) complex models available for research in implant dentistry. To accomplish this, a comprehensive search of the literature present on Scopus and PubMed databases was done using specific keywords, as well as inclusion/exclusion criteria. Out of 1334 articles found, we have finally included 27 articles in this review with publication dates between 2001 and 2022. In those articles, the 3D models were designed to study tissue-implant interface behavior in bone or gingival tissue. The articles focused on simulating implant integration, evaluating the effect of different conditions on implant integration, or developing an infection model for the implant integration process. The methods used involved implant material and cells organized in a specific 3D structure. The 3D models developed were able to simulate the process of dental implant osseo- and soft tissue integration and lead to results comparable with conventional in vitro and in vivo models. A relatively limited number of articles were obtained, which indicates that this is an emerging field, highly dependent on progresses made in biotechnologies and tissue engineering, and that further investigation is needed to enhance these 3D in vitro models.

Harnessing Human Placental Membrane-Derived Bioinks: Characterization and Applications in Bioprinting and Vasculogenesis.

Bioprinting applications in the clinical field generate great interest, but developing suitable biomaterial inks for medical settings is a challenge. Placental tissues offer a promising solution due to their abundance, stability, and status as medical waste. They contain basement membrane components, have a clinical history, and support angiogenesis. This study formulates bioinks from two placental tissues, amnion (AM) and chorion (CHO), and compares their unique extracellular matrix (ECM) and growth factor compositions. Rheological properties of the bioinks are evaluated for bioprinting and maturation of human endothelial cells. Both AM and Cho-derived bioinks sustained human endothelial cell viability, proliferation, and maturation, promoting optimal vasculogenesis. These bioinks derived from human sources have significant potential for tissue engineering applications, particularly in supporting vasculogenesis. This research contributes to the advancement of tissue engineering and regenerative medicine, bringing everyone closer to clinically viable bioprinting solutions using placental tissues as valuable biomaterials.

Laser-assisted 3D bioprinting of exocrine pancreas spheroid models for cancer initiation study.

Pancreatic ductal adenocarcinoma (PDAC) is the most common malignancy of the pancreas. It has shown a poor prognosis and a rising incidence in the developed world. Other pathologies associated with this tissue include pancreatitis, a risk condition for pancreatic cancer. The onset of both pancreatitis and pancreatic cancer follows a common pattern: exocrine pancreatic acinar cells undergo a transdifferentiation to duct cells that triggers a 3D restructuration of the pancreatic tissue. However, the exact mechanism underlying this process remains partially undefined. Further understanding the cellular events leading to PDAC could open new avenues in the development of novel therapeutic approaches. Since current 2D cell culture models fail to mimic the tridimensional complexity of the pancreatic tissue, new in vitro models are urgently needed. Here, we generated 3D pancreatic cell spheroid arrays using laser-assisted bioprinting and characterized their phenotypic evolution over time through image analysis and phenotypic characterization. We show that these bioprinted spheroids, composed of both acinar and ductal cells, can replicate the initial stages of PDAC development. This bioprinted miniaturized spheroid-based array model should prove useful for the study of the internal and external factors that contribute to the formation of precursor PDAC lesions and to cancer progression, and may therefore shed light on future PDAC therapy strategies.

Histopathological and molecular study for synchronous lung adenocarcinoma staging.

The presence of multiple synchronous lung cancer with the same histopathological type for a patient is a common situation and an issue for staging. Pathological criteria exist to distinguish multiple primaries from intra-pulmonary metastases of the same tumor, but they lack standardization. We wondered how molecular analysis with a limited Next Generation Sequencing panel could bring further information for tumor staging in this setting. We analyzed 24 patients with a total of 50 tumor nodules (22 pairs, two triplets). We compared histopathological examination with molecular analysis. A total of 50 tumors were molecularly tested. Nucleoli size was associated with molecular analysis concordance (p = 0.047). The presence of lepidic component in any of the two larger tumors was associated with molecular analysis concordance (p = 0.012). For molecular analysis, the proportion of progression-free patients was at the limits of significance (p = 0.054) whereas the presence of lepidic component, architectural concordance, and the concordance of comprehensive histologic assessments was not related to progression-free survival. For two patients with a discordant TTF-1 immunohistochemistry, molecular analysis showed a different mutation. Our results show that a limited NGS panel brings supplementary data to classify synchronous lung adenocarcinoma in most patients. We show that molecular staging seems in accordance with progression-free survival. Histopathological examination alone might not be accurate enough to assess a correct staging for synchronous tumors. We also suggest that TTF-1 immunohistochemistry, for the rare discrepant cases, might be a surrogate to molecular analysis.

MLH1 promoter hypermethylation: are you absolutely sure about the absence of MLH1 germline mutation? About a new case.

Lynch syndrome accounts for 3-5% of colorectal cancers and is due to a germline mutation in one of the mismatch repair genes MLH1, MSH2, MSH6, and PMS2. Somatic hypermethylation of the MLH1 promoter is commonly associated to sporadic cases. Strategies have been developed to identify patients with Lynch Syndrome based on clinical findings, tumoral phenotype, family history and immunohistochemistry analysis. However, there still are some pitfalls in this strategy, possibly responsible for an underdiagnosis of Lynch syndrome. Here we report the case of a 37 years-old man presenting with two concomitant tumors located in the rectosigmoid and in the ileocecal angle. Both tumors were microsatellites instability-high (MSI-H) and showed a loss of MLH1 and PMS2 protein expression, but only one had MLH1 promoter hypermethylation. Constitutional analysis of mismatch repair genes could not be performed from a blood sample, because of the early death of the patient. However, tumoral tissue analyses revealed in both tumors a pathogenic variant in the MLH1 gene. Further analysis of the surrounding tumor-free tissue also showed the presence of this alteration of the MHL1 gene. Finally, the same pathogenic variant was present constitutionally in one of the siblings of the patient, confirming its hereditary nature. This new case of concomitant presence of MLH1 promoter hypermethylation and MLH1 germline mutation demonstrates that the presence of MLH1 promoter hypermethylation should not rule out the diagnosis of Lynch Syndrome.

Lepidic, Papillary Components and EGFR Mutations are Frequent in Patients With Lung Adenocarcinoma Who are Over 75 Years Old.

Treatment for lung adenocarcinoma frequently diverges from standard treatment in older patients. Clinical, pathologic, and molecular characteristics of lung cancer in patients over 75 years old have not been fully described. The aim of our work was to describe the rate of EGFR, KRAS, BRAF, and HER2 mutations, and ALK rearrangement and pathologic characteristics in patients with lung adenocarcinoma over 75, compared with patients below 75 years old. This is a retrospective study from 2 cohorts: a histopathologic cohort of all consecutively resected lung adenocarcinoma in our institution for patients over 75 (n=54, from 2006 to 2017) compared with patients below 75 years old (n=148, from 2014 to 2017) and a molecular cohort of all stage IIIb or IV lung adenocarcinoma from 2009 to 2017 (n=1611). Papillary and lepidic components were more frequently found in patients over 75 years old (P=0.046 and 0.0078, respectively). The rate of current smokers was lower in older patients (P<0.0001). EGFR mutations were more frequent in patients over 75 than in younger patients: 17% versus 8.1% (P<0.0001). The mutually exclusive KRAS mutation was more frequent in patients below 75 years old than in older patients: 25.8% versus 12.8% (P<0.0001). There was no difference for the proportion of the 2 most frequent EGFR mutations (exon 19 deletion and L858R mutation) (P=0.85) or KRAS-mutated codon (P=0.22) between tumors in younger or older patients. There was no statistically significant difference for the presence of BRAF, HER2 mutations, and ALK rearrangement (P=0.44, 0.71, and 1, respectively). Our work highlights the fact that EGFR mutations are more frequent in patients over 75 years old in our population. We can hypothesize that this difference might be mainly caused by the less frequent occurrence of tobacco-smoking-related lung cancers in the elderly and the presence of a lepidic or papillary component in this age group.

Ovarian neuroendocrine carcinoma of metastatic origin: clues for diagnosis.

Neuroendocrine tumors of the ovary are rare and of uncertain histogenesis. They may be primary or metastatic. Pathogenesis of ovarian carcinomas remains unknown. We report the case of an ovarian large cell carcinoma expressing all neuroendocrine markers (CD56, chromogranin A, synaptophysin) that presented as a primary tumor and coexisted with a typical endometrial serous carcinoma also expressing one neuroendocrine marker (CD56). The 2 tumors had identical molecular mutational profiles as examined by next-generation sequencing. We propose that the ovarian neuroendocrine tumor was metastatic from an endometrial serous carcinoma with limited neuroendocrine differentiation.

Pericardial and Pleural Metastases: Clinical, Histologic, and Molecular Differences.

BACKGROUND: Pericardial and pleural cavities produce effusions with important clinical consequences. Metastases are one of the most common etiologies of both serosal effusions. However, data regarding the type of metastatic involvement of the pleura and the pericardium are lacking. This study investigated the histologic patterns of tumors involving the two cavities to better define their pathophysiology and possible consequences in molecular diagnostics. METHODS: This was a retrospective study of patients diagnosed with pericardial (n = 75) and pleural (n = 70) metastases. Patterns of metastasis were characterized as (1) tumor cells floating inside the cavity (2) as lymphatic emboli and (3) as tumor cells frankly invading underlying fibrous tissue. Molecular analysis (EGFR, KRAS, BRAF, ALK, HER2) was performed in 44 metastases of lung adenocarcinomas. RESULTS: The two serosal membranes differed significantly (p < 0.0001) in the pattern of metastasis. The pleura showed predominantly an invasive pattern (67 [95.7%]), whereas most pericardial metastases consisted of tumor cells floating inside the cavity or as lymphatic emboli (44 [58.6%]). The origin of the primary differed marginally between the two organs. Time to diagnosis of metastasis differed between the two organs, with pleural metastases presenting later than the pericardial ones. Molecular analysis failed more often in pericardial biopsy specimens and in specimens with emboli or surface involvement. CONCLUSIONS: Although pericardium and pleura share common embryologic and histologic features and are often regarded as giving similar effusions, they differ significantly in the type of metastases involving them. This can have important consequences in histologic, cytologic, and molecular diagnostics.

EGFR, KRAS, BRAF and HER2 testing in metastatic lung adenocarcinoma: Value of testing on samples with poor specimen adequacy and analysis of discrepancies.

Molecular testing on metastatic lung adenocarcinoma or on non-small cell non-squamous lung carcinoma often relies on small specimen. In this group of patient with poor specimen adequacy, we analyzed the rate of EGFR, KRAS, BRAF and HER2 mutations compared to their rate in optimal specimen. We analyzed discrepancies in molecular testing results in patients with iterative analysis on several samples. We performed a retrospective study of 1538 samples consecutively analyzed. 263/665 (39,5%) biopsies and 37/708 (5,2%) surgical specimens were considered as samples with poor specimen adequacy (p<0,0001). A lower tumor cell content was associated with a lower rate of KRAS mutation: 15,8% in samples with <10% of tumor cells or <100 tumor cells versus 29,8% in samples with >10% tumor cell and >100 tumor cells (p=0,001). KRAS mutational rate was at 11,1% in cytology specimens, significantly lower than in biopsy or surgical specimens respectively at 28,2% and 28,5% (p=0,0002). Tumor cell content was not associated with mutational rate for EGFR, BRAF and HER2 mutations. DNA quantity was not associated with mutational rate for EGFR, KRAS, BRAF and HER2. A discrepancy in molecular testing was found in 16 patients. For 5 patients there was also a discrepancy for TTF-1 expression. On the 11 without TTF-1 discrepancy, specimen adequacy was not fulfilled in 10 cases at least for tumor content. Discrepancies were found in the case of low cellularity, poor cell content or testing on cytological specimens. Tumor cell content is a crucial parameter for molecular analysis rather than the type of specimen or the DNA quantity. Discrepancies in molecular testing results are rare but might suggest the presence of another tumor type, the emergence of another clone or a molecular testing in a sample with low cell content.

PD-L1 expression in pleomorphic, spindle cell and giant cell carcinoma of the lung is related to TTF-1, p40 expression and might indicate a worse prognosis.

Lung sarcomatoid carcinoma of the lung is a rare tumor with a poor prognosis. More than 90% of them are pleomorphic, spindle cell and giant cell carcinoma (PSCGCC). This rare subtype of lung cancer is thought to be more resistant to chemotherapy, and a small subset of them seems to exhibit targetable mutations. Immunotherapy against PD1/PDL-1 is a new emerging treatment, and might be of interest in PSGSCC because they frequently express PD-L1. The aim of our work is to evaluate PD1 and PDL-1 expression in a surgical series of lung PSCGCC and their relationship with morphological and immunohistochemical parameters and prognosis. Thirty-six patients who underwent surgical resection of a PSGSCC were included. PD-L1 (E1L3N) expression on tumor cells and PD1 (NAT105) expression by tumor infiltrating lymphocytes (TILs) were performed by immunohistochemistry. Results were compared to immunohistochemistry tests of TTF1, Napsin A, p40 and to molecular study of EGFR, KRAS, BRAF and HER2. Seventy-five % of PSCGCC were considered as positive for PD-L1.PD-L1 expression in PSGSCC is associated with TTF-1 and/or Napsin A expression (47.2%, p = 0.039). Few p40 positive PSCGCC expressed PD-L1 (8.3%, p = 0.013). PD1 expression was not related to TTF-1 and/or Napsin A expression (p = 0.47), p40 expression (p = 0.68) or survival (p = 0.14). PD-L1 or PD1 expression were not related to the age, gender, pT, pN, stage, visceral pleura invasion, histopathological subtype, the presence of giant cell component, the predominance of sarcomatoid component, and the presence of EGFR or BRAF or HER2 or PIK3CA mutation (p>0.05). PD-L1 expression was correlated with a worse overall survival in PSCGCC (p = 0.045). PD-L1 expression is frequent in PSCGCC and might be associated with the expression of adenocarcinoma markers (TTF-1, Napsin A) or the lack of expression of squamous cell carcinoma marker (p40).

Histomolecular profiling of pleomorphic, spindle cell, and giant cell carcinoma of the lung for targeted therapies.

In pleomorphic, spindle cell, and giant cell carcinoma (PSCGC) of the lung, we wondered if an integrated diagnosis including morphological and immunohistochemical features could be related to molecular status. We performed immunohistochemistry on 35 PSCGCs against TTF1, napsin A, p40, ALK, ROS1, and c-MET. Mutational status regarding EGFR, KRAS, BRAF, HER2, and PIK3CA genes was established. Of 18 PSCGCs with adenocarcinomatous or "undifferentiated" carcinoma differentiation, 8 were mutated for EGFR (n = 1), KRAS (n = 2), BRAF (n = 1), HER2 (n = 3), and PIK3CA (n = 1). No PSCGC (0/4) with only squamous cell or adenosquamous (0/2) differentiation was mutated. c-MET overexpression was only seen in PSCGC with adenocarcinomatous or undifferentiated component (n = 5) without squamous cell component. ROS1 and ALK were negative. The presence of a "targetable mutation" was correlated to the presence of morphological or immunohistochemical adenocarcinomatous differentiation (P = .0137). Integrated diagnosis of an adenocarcinomatous component in PSCGC could be associated with the presence of targetable gene mutation. Because only PSCGC with adenocarcinomatous or undifferentiated carcinoma harbors mutations, whereas PSCGC with only squamous or adenosquamous differentiation does not in our study, this might represent a prescreening for patients with PSCGC to be tested for molecular targets. Our results emphasize that careful morphological examination and the use of immunohistochemistry might be useful for the selection of PSCGC tested for a mutational target.