156 research outputs found
Performance of p16INK4a ELISA as a primary cervical cancer screening test among a large cohort of HIV-infected women in western Kenya: a 2-year cross-sectional study.
ObjectiveA biomarker with increased specificity for cervical dysplasia compared with human papillomavirus (HPV) testing would be an attractive option for cervical cancer screening among HIV-infected women in resource-limited settings. p16(INK4a) has been explored as a biomarker for screening in general populations.DesignA 2-year cross-sectional study.Setting2 large HIV primary care clinics in western Kenya.Participants1054 HIV-infected women in western Kenya undergoing cervical cancer screening as part of routine HIV care from October 2010 to November 2012.InterventionsParticipants underwent p16(INK4a) specimen collection and colposcopy. Lesions with unsatisfactory colposcopy or suspicious for cervical intraepithelial neoplasia 2+ (CIN2+; including CIN2/3 or invasive cervical cancer) were biopsied. Following biopsy, disease status was determined by histopathological diagnosis.Primary and secondary outcome measuresWe measured the sensitivity, specificity and predictive values of p16(INK4a) ELISA for CIN2+ detection among HIV-infected women and compared them to the test characteristics of current screening methods used in general as well as HIV-infected populations.ResultsAverage p16(INK4a) concentration in cervical samples was 37.4â
U/mL. After colposcopically directed biopsy, 127 (12%) women were determined to have CIN2+. Receiver operating characteristic analysis showed an area under the curve of 0.664 for p16(INK4a) to detect biopsy-proven CIN2+. At a p16(INK4a) cut-off level of 9â
U/mL, sensitivity, specificity, positive and negative predictive values were 89.0%, 22.9%, 13.6% and 93.8%, respectively. The overall p16(INK4a) positivity at a cut-off level of 9â
U/mL was 828 (78.6%) women. There were 325 (30.8%) cases of correct p16(INK4a) prediction to detect or rule out CIN2+, and 729 (69.2%) cases of incorrect p16(INK4a) prediction.Conclusionsp16(INK4a) ELISA did not perform well as a screening test for CIN2+ detection among HIV-infected women due to low specificity. Our study contributes to the ongoing search for a more specific alternative to HPV testing for CIN2+ detection
Frameshift mutations in coding repeats of protein tyrosine phosphatase genes in colorectal tumors with microsatellite instability
<p>Abstract</p> <p>Background</p> <p>Protein tyrosine phosphatases (PTPs) like their antagonizing protein tyrosine kinases are key regulators of signal transduction thereby assuring normal control of cellular growth and differentiation. Increasing evidence suggests that mutations in PTP genes are associated with human malignancies. For example, mutational analysis of the tyrosine phosphatase (PTP) gene superfamily uncovered genetic alterations in about 26% of colorectal tumors. Since in these studies tumors have not been stratified according to genetic instability status we hypothesized that colorectal tumors characterized by high-level of microsatellite instability (MSI-H) might show an increased frequency of frameshift mutations in those PTP genes that harbor long mononucleotide repeats in their coding region (cMNR).</p> <p>Results</p> <p>Using bioinformatic analysis we identified 16 PTP candidate genes with long cMNRs that were examined for genetic alterations in 19 MSI-H colon cell lines, 54 MSI-H colorectal cancers, and 17 MSI-H colorectal adenomas. Frameshift mutations were identified only in 6 PTP genes, of which PTPN21 show the highest mutation frequency at all in MSI-H tumors (17%).</p> <p>Conclusion</p> <p>Although about 32% of MSI-H tumors showed at least one affected PTP gene, and cMNR mutation rates in PTPN21, PTPRS, and PTPN5 are higher than the mean mutation frequency of MNRs of the same length, mutations within PTP genes do not seem to play a common role in MSI tumorigenesis, since no cMNR mutation frequency reached statistical significance and therefore, failed prediction as a Positive Selective Target Gene.</p
p16INK4a/Ki-67 dual stain cytology for cervical cancer screening in Thika district, Kenya
Background: The identification of suited early detection tests is one among the multiple requirements to reduce cervical cancer incidence in developing countries. Methods: We evaluated p16INK4a/Ki-67 dual-stain cytology in a screening population in Thika district, Kenya and compared it to high-risk human papillomavirus (HR-HPV) DNA testing and visual inspection by acetic acid (VIA) and Lugolâs iodine (VILI). Results: Valid results for all tests could be obtained in 477 women. 20.9Â % (100/477) were tested positive for HR-HPV DNA, 3.1Â % (15/477) had positive VIA/VILI and 8.2Â % (39/477) positive p16INK4a/Ki-67 cytology. Of 22 women that showed up for colposcopy and biopsy, 6 women were diagnosed with CIN3 and two with CIN2. All women with CIN2/3 were negative in VIA/VILI screening and positive by HR-HPV DNA testing. But HPV was also positive in 91.7Â % (11/12) of women with normal histology. p16INK4a/Ki-67 cytology was positive in all 6 women with CIN3, in one of the two CIN2 and in only 8.3Â % (1/12) of women with normal histology. Conclusions: p16INK4a/Ki-67 cytology is an interesting test for further studies in developing countries, since our findings point to a lower fraction of false positive test results using p16INK4a/Ki-67 cytology compared to HPV DNA testing in a Kenyan screening population. VIA/VILI missed all histology-proven CIN2/3
Molecular Alterations and Association with Clinical Parameters
Lynch syndrome is caused by germline mutations of DNA mismatch repair (MMR)
genes, most frequently MLH1 and MSH2. Recently, MMR-deficient crypt foci (MMR-
DCF) have been identified as a novel lesion which occurs at high frequency in
the intestinal mucosa from Lynch syndrome mutation carriers, but very rarely
progress to cancer. To shed light on molecular alterations and clinical
associations of MMR-DCF, we systematically searched the intestinal mucosa from
Lynch syndrome patients for MMR-DCF by immunohistochemistry. The identified
lesions were characterised for alterations in microsatellite-bearing genes
with proven or suspected role in malignant transformation. We demonstrate that
the prevalence of MMR-DCF (mean 0.84 MMR-DCF per 1 cm2 mucosa in the
colorectum of Lynch syndrome patients) was significantly associated with
patientsâ age, but not with patientsâ gender. No MMR-DCF were detectable in
the mucosa of patients with sporadic MSI-H colorectal cancer (n = 12).
Microsatellite instability of at least one tested marker was detected in 89%
of the MMR-DCF examined, indicating an immediate onset of microsatellite
instability after MMR gene inactivation. Coding microsatellite mutations were
most frequent in the genes HT001 (ASTE1) with 33%, followed by AIM2 (17%) and
BAX (10%). Though MMR deficiency alone appears to be insufficient for
malignant transformation, it leads to measurable microsatellite instability
even in single MMR-deficient crypts. Our data indicate for the first time that
the frequency of MMR-DCF increases with patientsâ age. Similar patterns of
coding microsatellite instability in MMR-DCF and MMR-deficient cancers suggest
that certain combinations of coding microsatellite mutations, including
mutations of the HT001, AIM2 and BAX gene, may contribute to the progression
of MMR-deficient lesions into MMR-deficient cancers
Genital self-sampling for HPV-based cervical cancer screening: a qualitative study of preferences and barriers in rural Ethiopia
Background In the context of WHOâs âtask shiftingâ project and growing global consensus on primary HPV-based cervical cancer screening, self-sampling is a promising new tool to expand screening access, uptake and coverage for women worldwide. We aimed to explore perceptions and acceptability of HPV self-sampling-based cervical cancer screening among community members and health professionals in rural northwest Ethiopia and to identify preferences and socio-cultural barriers regarding self-sampling in order to design a suitable high-coverage screening intervention for a rural African setting.
Methods: Four community-based focus group discussions (FGD) were conducted in the rural district of Dabat, Northwest Ethiopia, each comprising 8 to 14 female participants, counting a total of 41 participants. The groups were homogenously composed in terms of their socio-economic status in the community. They included health centre attendees, community members, nurses and health development army leaders (HDAL). Two qualitative data collection experts conducted the interviews in the local language, using a FGD guide with several thematic areas. All participants granted written informed consent prior to the conduct of the interviews. As a concrete example of an existing self-sampling approach for cervical cancer screening we used the EvalynÂź Brush.
Results: Emerging themes included (i) misconceptions and low awareness about cervical cancer among community residents and primary health care providers in rural northwest Ethiopia, (ii) stigmatization and social exclusion of affected women, (iii) delay in seeking of health care due to poor access and availability of services, and lacking of a concept of early cancer prevention, (iv) need of spousal permission, (v) fear of financial burden and (vi) fear of social marginalization. The self-sampling device was regarded to be acceptable and was judged to be easy to use for most women. The existing Ethiopian health care structure could facilitate a community approach.
Conclusion: Home-based self-sampling for cervical cancer screening is a socially acceptable and feasible âtask shiftingâ method that will increase cervical cancer screening access and coverage in the Ethiopian study community. Education, awareness creation, community mobilization and family inclusion are identified as key activities to promote, implement and facilitate âtask shiftingâ approaches like self-sampling
Beta-2-microglobulin Mutations Are Linked to a Distinct Metastatic Pattern and a Favorable Outcome in Microsatellite-Unstable Stage IV Gastrointestinal Cancers
Immune checkpoint blockade (ICB) shows remarkable clinical effects in patients with
metastatic microsatellite-unstable (MSI) cancer. However, markers identifying potential
non-responders are missing. We examined the prevalence of Beta-2-microglobulin (B2M)
mutations, a common immune evasion mechanism, in stage IV MSI gastrointestinal
cancer and its influence on metastatic pattern and patientsâ survival under ICB. Twentyfive
patients with metastatic, MSI gastrointestinal adenocarcinoma were included.
Eighteen patients received ICB with pembrolizumab and one patient with nivolumab/
ipilimumab. Sequencing was performed to determine B2M mutation status. B2M
mutations and loss of B2M expression were detected in 6 out of 25 stage IV MSI
cancers. B2M mutations were strongly associated with exclusively peritoneal/peritoneal
and lymph node metastases (p=0.0055). However, no significant differences in therapy
response (25% vs. 46.6%, p>0.99) and survival (median PFS: 19.5 vs 33.0 months,
p=0.74; median OS 39 months vs. not reached, p>0.99) were observed between B2Mmutant
and B2M-wild type tumor patients. Among metastatic MSI GI cancers, B2Mmutant
tumors represent a biologically distinct disease with distinct metastatic patterns.
To assess ICB response in B2M-mutant MSI cancer patients, future studies need to
account for the fact that baseline survival of patients with B2M-mutant MSI cancer may be
longer than of patients with B2M-wild type MSI cancer
Beta-2-microglobulin Mutations Are Linked to a Distinct Metastatic Pattern and a Favorable Outcome in Microsatellite-Unstable Stage IV Gastrointestinal Cancers
Immune checkpoint blockade (ICB) shows remarkable clinical effects in patients with metastatic microsatellite-unstable (MSI) cancer. However, markers identifying potential non-responders are missing. We examined the prevalence of Beta-2-microglobulin (B2M) mutations, a common immune evasion mechanism, in stage IV MSI gastrointestinal cancer and its influence on metastatic pattern and patientsâ survival under ICB. Twenty-five patients with metastatic, MSI gastrointestinal adenocarcinoma were included. Eighteen patients received ICB with pembrolizumab and one patient with nivolumab/ipilimumab. Sequencing was performed to determine B2M mutation status. B2M mutations and loss of B2M expression were detected in 6 out of 25 stage IV MSI cancers. B2M mutations were strongly associated with exclusively peritoneal/peritoneal and lymph node metastases (p=0.0055). However, no significant differences in therapy response (25% vs. 46.6%, p>0.99) and survival (median PFS: 19.5 vs 33.0 months, p=0.74; median OS 39 months vs. not reached, p>0.99) were observed between B2M-mutant and B2M-wild type tumor patients. Among metastatic MSI GI cancers, B2M-mutant tumors represent a biologically distinct disease with distinct metastatic patterns. To assess ICB response in B2M-mutant MSI cancer patients, future studies need to account for the fact that baseline survival of patients with B2M-mutant MSI cancer may be longer than of patients with B2M-wild type MSI cancer
The coding microsatellite mutation profile of PMS2-deficient colorectal cancer
Lynch syndrome (LS) is caused by a pathogenic heterozygous germline variant in one of the DNA mismatch repair (MMR) genes: MLH1, MSH2, MSH6 or PMS2. LS-associated colorectal carcinomas (CRCs) are characterized by MMR deficiency and by accumulation of multiple insertions/deletions at coding microsatellites (cMS). MMR deficiency-induced variants at defined cMS loci have a driver function and promote tumorigenesis. Notably, PMS2 variant carriers face only a slightly increased risk of developing CRC. Here, we investigate whether this lower penetrance is also reflected by differences in molecular features and cMS variant patterns. Tumor DNA was extracted from formalin-fixed paraffin-embedded (FFPE) tissue cores or sections (n = 90). Tumors originated from genetically proven germline pathogenic MMR variant carriers (including 14 PMS2-deficient tumors). The mutational spectrum was analyzed using fluorescently labeled primers specific for 18 cMS previously described as mutational targets in MMR-deficient tumors. Immune cell infiltration was analyzed by immunohistochemical detection of T-cells on FFPE tissue sections. The cMS spectrum of PMS2-deficient CRCs did not show any sig-nificant differences from MLH1/MSH2-deficient CRCs. PMS2-deficient tumors, however, displayed lower CD3-positive T-cell infiltration compared to other MMR-deficient cancers (28.00 vs. 55.00 per 0.1 mm(2), p = 0.0025). Our study demonstrates that the spectrum of potentially immunogenic cMS variants in CRCs from PMS2 gene variant carriers is similar to that observed in CRCs from other MMR gene variant carriers. Lower immune cell infiltration observed in PMS2-deficient CRCs could be the result of alternative mechanisms of immune evasion or immune cell exclusion, similar to those seen in MMR-proficient tumors.Hereditary cancer genetic
Organotypic Co-Cultures as a Novel 3D Model for Head and Neck Squamous Cell Carcinoma
Background: Head and neck squamous cell carcinomas (HNSCC) are phenotypically and
molecularly heterogeneous and frequently develop therapy resistance. Reliable patient-derived 3D
tumor models are urgently needed to further study the complex pathogenesis of these tumors and
to overcome treatment failure. Methods: We developed a three-dimensional organotypic co-culture
(3D-OTC) model for HNSCC that maintains the architecture and cell composition of the individual
tumor. A dermal equivalent (DE), composed of healthy human-derived fibroblasts and viscose fibers,
served as a scaffold for the patient sample. DEs were co-cultivated with 13 vital HNSCC explants
(non-human papillomavirus (HPV) driven, n = 7; HPV-driven, n = 6). Fractionated irradiation was
applied to 5 samples (non-HPV-driven, n = 2; HPV-driven n = 3). To evaluate expression of ki-67,
cleaved caspase-3, pan-cytokeratin, p16INK4a, CD45, âsmooth muscle actin and vimentin over time,
immunohistochemistry and immunofluorescence staining were performed Patient checkup data
were collected for up to 32 months after first diagnosis. Results: All non-HPV-driven 3D-OTCs
encompassed proliferative cancer cells during cultivation for up to 21 days. Proliferation indices of
primaries and 3D-OTCs were comparable and consistent over time. Overall, tumor explants displayed heterogeneous growth patterns (i.e., invasive, expansive, silent). Cancer-associated fibroblasts and
leukocytes could be detected for up to 21 days. HPV DNA was detectable in both primary and
3D-OTCs (day 14) of HPV-driven tumors. However, p16INK4a expression levels were varying.
Morphological alterations and radioresistant tumor cells were detected in 3D-OTC after fractionated
irradiation in HPV-driven and non-driven samples. Conclusions: Our 3D-OTC model for HNSCC
supports cancer cell survival and proliferation in their original microenvironment. The model enables
investigation of invasive cancer growth and might, in the future, serve as a platform to perform
sensitivity testing upon treatment to predict therapy response
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