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CDKN2A gene belongs to the genes involved in cell cycle regulation. When is absent or inactivated by mutation or promoter hypermethylation a cell may undertake an uncontrolled proliferation. Inactivation of CDKN2A gene is observed in many human malignancies, including larynx cancer. In this study we investigated mutations in exon 1 and exon 2 of CDKN2A gene in a large group of 390 laryngeal cancers. We found 40 different alterations (17%) and nearly half of them was not described previously. Out of these alterations two transversions in codon 108: c.322G>C (Asp108His) and c.322G>T (Asp108Tyr) as well as a G>A transition in codon 110 (Trp110X) were found more frequently (altogether: 7 cases in codon 108 and 10 cases in codon 110). This result, concerning the location of these codons in the ankyrin repeat structures, may suggest that these two codons may be critical hot-spots in larynx carcinogenesis.

Carcinogenesis may result from abnormal methylation of cancer-related genes regulatory sequence. Though, the polymorphic variants of genes encoding enzymes of folate and methionine metabolism may have an effect on DNA methylation. Using PCR-RFLPs, we examined the polymorphism distribution of genes encoding methionine synthase (MTR); 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase (MTHFD1); and methylenetetrahydrofolate reductase (MTHFR) in patients with larynx cancer (n = 131) and controls (n = 250). Patients with MTR 2756AG or GG genotypes displayed a 1.856 -fold increased risk of larynx cancer (95% CI = 1.1860–2.903, P = 0.0076). However, we did not observe an increased risk for the homozygous GG genotype OR = 1.960 (95% CI = 0.6722–5.713, P = 0.2535). Moreover, we did not observe statistical differences in distribution of MTHFR 677C>T, 1298A>C and MTHFD1 1958G>A allele and genotype frequencies in patients and controls. Our findings confirm the significance of the role of the methyl cycle in etiopathogenesis of laryngeal cancer.

Obtaining a good quality of RNA from small population of cells remain an issue. Isolation for a special anatomic location such as inner ear placed in the temporal bone become a challenge, especially in terms of time needed for isolation of living tissue from the bone, which is a key factor to preserve the RNA. Due to limited accessibility to the technologies such as laser dissection, we present a simplified procedure for isolation of good quality of RNA from the inner ear for further studies.

We reinvestigated rearrangements occurring in region q13 of chromosome 11 aiming to: (i) describe heterogeneity of the observed structural alterations, (ii) estimate amplicon size and (iii) identify of oncogenes involved in laryngeal cancer progression as potential targets for therapy. The study included 17 cell lines derived from laryngeal cancers and 34 specimens from primary laryngeal tumors. The region 11q13 was analyzed by fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH) and gene expression microarray. Next, quantitative real time PCR was used for chosen genes to confirm results from aCGH and gene expression microarray. The observed pattern of aberrations allows to distinguish three ways, in which gain and amplification involving 11q13 region may occur: formation of a homogeneously staining region; breakpoints in/near 11q13, which lead to the three to sevenfold increase of the copy number of 11q13 region; the presence of additional copies of the whole chromosome 11. The minimal altered region of gain and/or amplification was limited to ~1.8 Mb (chr.11:69,395,184–71,209,568) and comprised mostly 11q13.3 band which contain 12 genes. Five, out of these genes (CCND1, ORAOV1, FADD, PPFIA1, CTTN) had higher expression levels in comparison to healthy controls. Apart from CCND1 gene, which has an established role in pathogenesis of head and neck cancers, CTTN, ORAOV1 and FADD genes appear to be oncogene-candidates in laryngeal cancers, while a function of PPFIA1 requires further studies.

The online version of the original article can be found underdoi:10.1007/s11033-012-1465-7.M. Szaumkessel (&) D. Brauze M. Rydzanicz K. SzyfterInstitute of Human Genetics, Polish Academy of Sciences,ul. Strzeszynska 32, 60-479 Poznan, Polande-mail: marcinsz@man.poznan.plM. Karlik K. Szyfter W. Szyfter M. Wro´belDepartment of Otolaryngology, Poznan University of MedicalSciences, Poznan, Polande-mail: wrobmac@ump.edu.pl