METHODS
Sixty-one HNSCC patients and 30 healthy volunteers from Türkiye were included in this study. Genomic
DNA isolation was performed from peripheral blood samples. The MAP3K8 chromosome gene
region 10:30451254-30451972 was amplified by PCR reaction and sequencing was carried out by Sanger
sequencing protocol.
RESULTS
In the chromosome 10:30451254-30451972 region of MAP3K8 gene, 203 SNP codes were scanned.
Among them, rs303426 polymorphism was found as statistically significant between HNSCC patient
and control group. The results indicated that people who carry A allele either as being homozygote or
heterozygote have more risk in developing HNSCC.
CONCLUSION
MAP3K8 mutations are extremely rare in HNSCC. The results of this study may be important by
showing the relationship between this rare MAP3K8 SNP with the risk of HNSCC in Turkish patient
group.
Keywords: HNSCC; MAP3K8 gene; polymorphism; Turkish patient group
High-throughput approaches have been used in a
variety of studies to examine the genomic landscape of
HNSCC. These studies have revealed substantial singlenucleotide
polymorphisms and copy number changes
in some genes including DKN2A, NOTCH1, PIK3CA,
FAT1, HRAS, CASP8, and PTEN.[
MAP3K8 (COT or TPL-2) is one of the MAP3Ks
identified in mammals. The MAP3K8 protooncogene is
a member of serine/threonine protein kinase family and
is involved in MEK-1, MKK-6, SAPK, NFAT, and NF-kB
signaling pathways.[
The most prevalent type of genetic variation is single-
nucleotide polymorphism (SNP), which makes it a
perfect genetic susceptibility marker.[
Genomic DNA isolation was performed with QIAamp® DNA Blood Kit (Qiagen, Germany) by taking 3-4 mL of peripheral blood samples from both patient and control groups into EDTA-K3 containing tubes. The purity and concentration of the DNA samples were determined by spectrophotometric analyses at 260/280 nm (AlphaSpec™ µL Spectrophotometer/ Alpha Innotech Corp.).
Genotyping
The MAP3K8 chromosome gene region 10:30451254-
30451972 was amplified by polymerase chain reaction
(PCR) method using specific primers. Amplification
of chromosome 10:30451254-30451972 region
of MAP3K8 was carried out on a ThermoPCR system
in a 50 µl reaction mixture Easytag (TransGen
Biotech, China) containing 10 pmol of forward (5"-
AGTGGCACAACTTTCACTGG-3") and reverse (5"-
TTCCCCTTCTTTGTCCTTCGT-3") primers and 50
ng DNA. The PCR cycling conditions consisted of an
initial denaturation step at 95°C for 5 min, followed by
35 cycles of 94°C for 1 min, 59°C for 1 min, 72°C for 1
min, and final extension step at 72°C for 5 min.
PCR products (556 bp) were visualized by agarose gel electrophoresis using an imaging system (BioRAD). PCR products were purified and sequencing was carried out by Sanger sequencing protocol of BM Laboratory Systems, Türkiye. Sequences were analysed by MITOMAP and compared with MAP3K8 NCBI reference sequences. SNP codes scanned in the chromosome 10:30451254- 30451972 region were rs1165786690, rs992106145, rs1428294268, rs916397740, rs969226709, rs1389767633, rs1310273711, rs1588784059, rs1588784070, rs1588784076, rs1588784084, rs1588784091, rs528684092, rs1588784084, rs1588784091, rs528684092, rs1476531728, rs1460272230, rs750643003, rs1198270171, rs199659350, rs303426, rs1269607437, rs561885103, rs1047055406, rs762978091, rs1273420722, rs938490212, rs1056914097, rs912586791, rs1269607437, rs561885103, rs1047055406, rs762978091, rs1273420722, rs938490212, rs1056914097, rs912586791, rs944289256, rs1039952018, rs1441905915, rs886298297, rs899982207, rs944289256, rs1039952018, rs1441905915, rs886298297, rs899982207, rs1004746048, rs1011707949, rs112402171, rs1043419351, rs903602091, rs1004746048, rs1011707949, rs112402171, rs1043419351, rs903602091, rs1305549502, rs1408363348, rs1370298679, rs770580895, rs1375013768, rs1305549502, rs1408363348, rs1370298679, rs770580895, rs1375013768, rs1223867729, rs371032502, rs1408267915, rs1470229486, rs112249809, rs748215392, rs1356919636, rs145319860, rs773454053, rs763277014, rs533325307, rs774511606, rs1588784392, rs371032502, rs1408267915, rs1470229486, rs112249809, rs748215392, rs1356919636, rs145319860, rs773454053, rs763277014, rs533325307, rs774511606, rs1588784392, rs1373499805, rs760131672, rs1324968516, rs1200373560, rs768122949, rs776345267, rs1216536649, rs761372768, rs1588784392, rs1373499805, rs760131672, rs1324968516, rs1200373560, rs768122949, rs776345267, rs1216536649, rs761372768, rs764843243, rs1191283360, rs1431157160, rs1294907660, rs764843243, rs1191283360, rs1431157160, rs1294907660, rs1204969252, rs750107886, rs1029129071, rs954461874, rs960674093, rs1204969252, rs750107886, rs1029129071, rs954461874, rs960674093, rs373977741, rs1564370920, rs139293295, rs766203908, rs751299982, rs1019779505, rs1397742363, rs1305400973, rs754968500, rs373977741, rs1564370920, rs139293295, rs766203908, rs751299982, rs1019779505, rs1397742363, rs1305400973, rs754968500, rs1350423859, rs781104573, rs779977265, rs748268594, rs1357627827, rs1350423859, rs781104573, rs779977265, rs748268594, rs1357627827, rs867629514, rs1285357490, rs552197626, rs1415074739, rs1269803880, rs374471102, rs1157068245, rs867629514, rs1285357490, rs756197619, rs552197626, rs1415074739, rs1269803880, rs374471102, rs1157068245, rs1197852938, rs1375880577, rs1471537566, rs1471108707, rs1158768197, rs1411155958, rs919792786, rs1471072981, rs1471246335, rs1209036466, rs989465189, rs149199668, rs1197852938, rs1375880577, rs1471537566, rs1471108707, rs1158768197, rs1411155958, rs919792786, rs1471072981, rs1471246335, rs1209036466, rs989465189, rs149199668, rs190602161, rs561019825, rs534855846, rs944056598, rs980139999, rs1377479761, rs73247425, and rs1419173388.
Statistical Analysis
The Statistical Package for the Social Sciences (SPSS)
version 16.0 software was used for statistical analysis.
The frequencies of MAPK8 rs303426 SNP alleles and
genotypes were obtained by direct count and departure
from the Hardy-Weinberg equilibrium was evaluated
by Chi square analysis. p value smaller than 0.05 was
considered as statistically significant. Odd ratios (OR)
and 95% confidence intervals (CI) were also calculated.
MAP3K8 gene polymorphism (rs303426) in
HNSCC patients and control group subjects is listed in
Table
MAPK pathway mutations affect one-fifth of HNSCC
cases.[
Altered expression levels of MAP3K8 in tumor development
are highly contraversial.[
Several DNA sequence alterations were identified in
HNSCC upto now. These include frequent mutations in
several genes such as TP53, EGFR, CCND1, NOTCH1,
MET, and PIK3CA.[
Although somatic mtDNA alterations are the main
targets in the diagnosis and prognosis of different cancers
because they are only present in tumor tissue, the
difficulties in handling the conventional mode of cancer
diagnostics have required a shift into finding new areas
that explore biomarkers that are less or non-invasive with
readily available samples such as blood, urine, and saliva.
[
Limitations of the Study
Our study still has some limitations. The patient and
control numbers should be increased, and also, haplotype
analysis linking to MAP3K8 expression level in both
blood samples and tumor tissues is rather necessary.
Peer-review: Externally peer-reviewed.
Conflict of Interest: All authors declared no conflict of interest.
Ethics Committee Approval: The study was approved by the University of Health Sciences Dışkapı Yıldırım Beyazıt Training and Research Hospital Clinical Research Ethics Committee (no: 56/22, date: 12/11/2018).
Financial Support: None declared.
Authorship contributions: Concept - P.M.; Design - P.M., M.M.; Supervision - P.M.; Funding - P.M., M.M., S.Y.A., Ö.B.; Materials - M.M., Ö.B., G.S., M.H.K.; Data collection and/or processing - P.M., M.M., S.Y.A., Ö.B., G.S., M.H.K.; Data analysis and/or interpretation - P.M., S.Y.A.; Literature search - P.M., M.M.; Writing - P.M., M.M., S.Y.A.; Critical review - P.M., M.M., S.Y.A., Ö.B., G.S., M.H.K.