Kariem Sharaf

Dr. Kariem Sharaf

Department of Otolaryngology, University Hospital, LMU Munich
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
3 July 2020 in Cancers
Verified
Journal Article
Open access
PDF file
SHStefan Philipp Haider
Stefan Philipp Haider
TZTal Zeevi
Tal Zeevi
PBPhilipp Baumeister
Philipp Baumeister
CRChristoph A. Reichel
Christoph A. Reichel
KSKariem Sharaf
Kariem Sharaf
Sam PayabvashSam Payabvash
Sam Payabvash
Accurate risk-stratification can facilitate precision therapy in oropharyngeal squamous cell carcinoma (OPSCC). We explored the potential added value of baseline positron emission tomography (PET)/computed tomography (CT) radiomic features for prognostication and risk stratification of OPSCC beyond the American Joint Committee on Cancer (AJCC) 8th edition staging scheme. Using institutional and publicly available datasets, we included OPSCC patients with known human papillomavirus (HPV) status, without baseline distant metastasis and treated with curative intent. We extracted 1037 PET and 1037 CT radiomic features quantifying lesion shape, imaging intensity, and texture patterns from primary tumors and metastatic cervical lymph nodes. Utilizing random forest algorithms, we devised novel machine-learning models for OPSCC progression-free survival (PFS) and overall survival (OS) using “radiomics” features, “AJCC” variables, and the “combined” set as input. We designed both single- (PET or CT) and combined-modality (PET/CT) models. Harrell’s C-index quantified survival model performance; risk stratification was evaluated in Kaplan–Meier analysis. A total of 311 patients were included. In HPV-associated OPSCC, the best “radiomics” model achieved an average C-index ± standard deviation of 0.62 ± 0.05 (p = 0.02) for PFS prediction, compared to 0.54 ± 0.06 (p = 0.32) utilizing “AJCC” variables. Radiomics-based risk-stratification of HPV-associated OPSCC was significant for PFS and OS. Similar trends were observed in HPV-negative OPSCC. In conclusion, radiomics imaging features extracted from pre-treatment PET/CT may provide complimentary information to the current AJCC staging scheme for survival prognostication and risk-stratification of HPV-associated OPSCC.

25 June 2020 in Strahlentherapie und Onkologie
Verified
Journal Article
Open access
PDF file
MJMark Jakob
Mark Jakob
KSKariem Sharaf
Kariem Sharaf
MSMarkus Schirmer
Markus Schirmer
MLMartin Leu
Martin Leu
SKStefan Küffer
Stefan Küffer
JKJulia Kitz
Julia Kitz
Purpose: Cancer stem cells (CSCs) are held accountable for the progress of head and neck squamous cell carcinoma (HNSCC). In the presented study, the authors evaluated the prognostic value of CSC markers in two particular HNSCC cohorts. Methods: This two cohort study consisted of 85 patients with advanced stage HNSCC, treated with primary radio(chemo)therapy (pRCT), and 95 patients with HNSCC, treated with surgery and partially adjuvant radio(chemo)therapy. Overall survival (OS), disease-free survival (DFS), and disease-specific survival (DSS) were assessed. Samples were assessed for the expression of different molecular stem cell markers (ALDH1, BCL11B, BMI‑1, and CD44). Results: In the pRCT cohort, none of the baseline patient and tumor features exhibited a statistically significant relation with survival in either the cohort or the human papillomavirus (HPV)-stratified subcohorts. High expression of BMI‑1 significantly decreased OS and DFS, while high expression of CD44 decreased all modes of survival. Multivariate analysis showed significant prognostic influence for all tested CSC markers, with high BMI‑1 and CD44 decreasing survival (BMI-1: OS, DFS, DSS; CD44: OS, DFS) and high ALDH1 and BCL11B showing a beneficial effect on survival (ALDH1: OS, DFS; BCL11B: OS, DSS). In the surgical cohort, classical prognosticators such as HPV status, R1 resection, and nodal status in HPV-negative HNSCC played a significant role, but the tested CSC markers showed no significant effect on prognosis. Conclusion: Although validation in independent cohorts is still needed, testing for CSC markers in patients with advanced or late stage HNSCC might be beneficial, especially if many comorbidities exist or disease is irresectable. The findings might guide the development and earlier use of targeted therapies in the future.

23 April 2021 in Otology & Neurotology
Verified
Journal Article
Closed access
KSKariem Sharaf
Kariem Sharaf
IGIvo Grueninger
Ivo Grueninger
AHAnnalena Hilpert
Annalena Hilpert
Daniel Polterauer-Neuling (née Polterauer)Daniel Polterauer-Neuling (née Polterauer)
Daniel Polterauer-Neuling (née Polterauer)
VVVeronika Volgger
Veronika Volgger
JMJoachim Müller
Joachim Müller
Objective: Stapes surgery is considered an effective treatment in otosclerosis, but controversy remains regarding predictors of surgical outcome. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Patients: One hundred sixty three cases of stapes surgery between 2012 and 2019 were reviewed. Main Outcome Measures: Primary outcome measures were relative hearing improvement (relHI), defined as preoperative minus postoperative air conduction divided by preoperative air-bone gap (ABG), as well as relative ABG closure (relABGc), defined as preoperative ABG minus postoperative ABG divided by preoperative ABG. Univariate and multivariate linear regression analyses were performed to determine independent predictors for these outcomes. Results: Higher preoperative bone conduction (BC) and primary surgery (compared with revision) were independently associated with increased relHI (p = 0.001 and p = 0.004, respectively). Lower preoperative BC, higher preoperative ABG, primary surgery, and age were independently associated with increased relABGc (p = 0.0030, p < 0.001, p = 0.0214, and p = 0.0099, respectively). Sex did not predict surgical outcome. In patients with less than 20 dB preoperative ABG, likelihood of negative relABGc was increased (compared with 20–30 dB or >30 dB preoperative ABG, p = 0.0292, Fisher's exact test). This tendency was not significant for relHI (p = 0.074). Conclusions: Our findings demonstrate that calculating HI and ABGc in relation to preoperative ABG can reliably predict outcomes of stapes surgery. Both primary and revision stapes surgery are effective treatment options, but relative improvement is higher in primary cases. Preoperative BC, preoperative ABG, and age predict surgical outcomes as well. Otosclerosis patients with low preoperative ABG, especially less than 20 dB, should be counseled and selected cautiously regarding stapes surgery.

31 March 2020 in Anticancer Research
Verified
Journal Article
Closed access
PDF file
TETanja K. Eggersmann
Tanja K. Eggersmann
PBPhilipp Baumeister
Philipp Baumeister
JKJorg Kumbrink
Jorg Kumbrink
DMDoris Mayr
Doris Mayr
ESElisa Schmoeckel
Elisa Schmoeckel
JGJulia K. S. Gallwas
Julia K. S. Gallwas
Background/Aim: The incidence of human papilloma virus (HPV)-related head and neck squamous cell carcinoma (HNSCC) has been increasing in the last decades. Analysis of oral brushing or rinsing samples for screening or stratification could potentially improve screening and prevention. Patients and Methods: Oral brushes and mouthwashes were taken from 20 patients with HPV-associated HNSCC before definite therapy. HPV genotyping was performed for the detection of 14 high-risk HPV subtypes and correlated to DNA isolated from tumor tissue. Results: Ten of 20 patients were tested HPV positive by using either method. There was a significant correlation between macroscopic visibility of tumor and positive HPV detection (p<0.001) and HPV detection and tumor size (p<0.001). HPV was detected in all macroscopically visible tumors. Half of the HPV cases who had macroscopically invisible tumors were missed by both methods. Conclusion: Both techniques are limited in the detection of macroscopically non-visible and small tumors. Therefore, the application of these techniques for screening or diagnosis of HNSCC is not recommended.

19 July 2021 in Current Oncology
Verified
Journal Article
Open access
PDF file
KSKariem Sharaf
Kariem Sharaf
ALAxel Lechner
Axel Lechner
SHStefan Philipp Haider
Stefan Philipp Haider
RWRobert Wiebringhaus
Robert Wiebringhaus
CWChristoph Walz
Christoph Walz
PBPhilipp Baumeister
Philipp Baumeister
Cancer stem cells (CSCs) are accountable for the progress of head and neck squamous cell carcinoma (HNSCC). This exploratory study evaluated the expression of molecular CSC markers in different tissues of HNSCC patients. Tissue specimens of primary tumor, lymph node metastases and macroscopically healthy mucosa of 12 consecutive HNSCC patients, that were treated with surgery and adjuvant radio(chemo)therapy upon indication, were collected. Samples were assessed for the expression of p16 as a surrogate for HPV-related disease and different molecular stem cell markers (ALDH1A1, BCL11B, BMI-1, and CD44). In the cohort, seven patients had HPV-related HNSCC; six thereof were oropharyngeal squamous cell carcinoma. While expression of BMI-1 and BCL11B was significantly lower in healthy mucosa than both tumor and lymph node metastasis, there were no differences between tumor and lymph node metastasis. In the HPV-positive sub-cohort, these differences remained significant for BMI-1. However, no significant differences in these three tissues were found for ALDH1A1 and CD44. In conclusion, this exploratory study shows that CSC markers BMI-1 and BCL11B discriminate between healthy and cancerous tissue, whereas ALDH1A1 and CD44 were expressed to a comparable extent in healthy mucosa and cancerous tissues.

1 June 2021 in Cancers
Verified
Journal Article
Open access
PDF file
KSKariem Sharaf
Kariem Sharaf
TETanja K Eggersmann
Tanja K Eggersmann
SHStefan Philipp Haider
Stefan Philipp Haider
SSSabina Schwenk-Zieger
Sabina Schwenk-Zieger
JZJiefu Zhou
Jiefu Zhou
FHFrank Haubner
Frank Haubner
Human adipose-derived stem/stromal cells (ASCs) are increasingly used as auto-transplants in regenerative medicine to restore tissue defects or induce wound healing, especially in cancer patients. The impact of ASCs on squamous cell carcinoma of the upper aerodigestive tract (UAT) including head and neck and esophageal squamous cell carcinoma (HNSCC and ESCC) is not yet fully understood. ASCs were cultured from subcutaneous, abdominal lipoaspirates of five patients, who received auto-transplants to the head and neck. Supernatants were tested for paracrine effects in functional in vitro assays of proliferation of HNSCC tumor cell line FaDu and ESCC cell line Kyse30, and their cell migration/invasion capacities in Boyden chambers, in addition to endothelial tube formation assay using human umbilical vein endothelial cells (HUVECs). All ASC-derived supernatants enhanced proliferation of FaDu cells, invasive migration, and tube formation by HUVECs, compared to controls. Of five patients’ lipoaspirates, ASC-derived supernatants of four patients increased proliferation and invasive migration in Kyse30 cells. The data suggests that ASCs can promote tumor cell proliferation, invasiveness, and neo-angiogenesis in these tumor cell lines of the UAT and HUVEC in a paracrine manner. Although clinical studies on the subject of oncological safety are still needed, these findings emphasize the importance of complete tumor removal before ASCs are used in the head and neck.