Imprinting analyses of
IGF2 and
H19, loss of heterozygosity (LOH) analyses of
IGF2R and
CTCF and
Helicobacter pylori detection, were performed on 35 human laryngeal squamous cell carcinomas (LSCC). Forty-six percent of the tumors were heterozygous
for
IGF2, and 54% were informative for the
H19. Biallelic expression of
IGF2 was observed in 33% (5 out of 15) of the tumors and in 27% (4 out of 15) of adjacent non-tumorous laryngeal tissues.
H19 loss of imprinting (LOI) was observed in 24% (4 out of 17) of the tumors. For
IGF2R and
CTCF, 71% (25 out of 35) and 50% (17/34), respectively, of the samples were heterozygous, and LOH was detected in 12% (3 out of
25) and 6% (1 out of 17), respectively, of the tumors.
H. pylori was found in 26% (9/35) of these tumors. Among them, four were informative for the imprinting analysis. The presence of
H. pylori had no effect on
IGF2/H19 imprinting. Only the
H. pylori detection was further broadened with an additional 47 laryngeal tumors, resulting in a total final positivity of close to
16% (13 out of 82). This study represents the largest comprehensive
IGF2/H19 imprinting study done to date on well-defined samples of human laryngeal carcinomas and corresponding non-tumorous tissue.
For the first time, the analyses of
IGF2/H19 imprinting have been broadened with LOH analyses of
IGF2R and
CTCF, with both of these genes acting as modulators of
IGF2 and
H19 activity. Although there were indications that
H. pylori may be present in LSCC, we are the first to show its presence in LSCC by two direct techniques: Giemsa staining and nested-PCR.
Keywords Laryngeal squamous cell carcinoma -
IGF2 LOI -
H19 LOI -
IGF2R LOH -
CTCF LOH -
Helicobacter pylori