Visualization of INT2 and HST1 Amplification in oral squamous cell carcinomas

Abstract

Oral squamous cell carcinoma (OSCC) develops along a multistep genetic pathway including loss of tumor suppressor genes and alteration of oncogenes. We characterized seven OSCC cell lines by classical and molecular cytogenetic analysis and fresh tumor and adjacent oral mucosa corresponding to three of the cell lines by molecular cytogenetics. We observed homogeneously staining regions (hsrs) in four of the seven cell lines, at 11q13 in three and at 11q23 and in an unidentified marker chromosome in the fourth. Amplification of band 11q13 occurs in 30-60% of head and neck squamous cell carcinomas. To determine whether INT2 and HST1, both located in band 11q13, are amplified in the tissues and cell lines and to confirm the chromosomal location(s) of the amplification, we used dual-color fluorescence in situ hybridization (FISH) with DNA probes for these genes and the chromosome 11 centromere. We report chromosomal localization of INT2/HST1 amplification in OSCC. Coamplification of INT2 and HST1 was detected in the hsrs in cultured tumor cells from the four hsr-containing tumors and in directly harvested tumor cells, which were available from only two of these tumors. Amplification was not present in tumors lacking hsrs or adjacent oral mucosa corresponding to any of the seven tumors. The observation of amplification in fresh tumor cells suggests that the amplification was present in the patients, may play a key role in the development and/or progression of OSCC, and is not due to karyotypic evolution in vitro. The absence of amplification in the adjacent mucosa suggests that 11q13 amplification is a relatively late event in OSCC tumorigenesis.

Dysregulated cyclin D1 expression early in head and neck tumorigenesis: in vivo evidence for an association with subsequent gene amplification

“…Most of the early speci®c genetic changes previously described involve mutations, deletions, loss of heterozygosity and chromosomal rearrangements. In contrast, the timing of gene ampli®cation is less well understood and several studies have suggested that proto-oncogene amplification is observed late in the progression of many tumors (reviewed in Brison, 1993;Lese et al, 1995). This has been supported, in the past, by the in vitro-derived notion that permissiveness for ampli®cation requires the disruption of several checkpoint mechanisms, often a hallmark of transformed cells.…”

Chromosomal imbalances in oral squamous cell carcinoma: Examination of 31 cell lines and review of the literature

“…), i(3)(q10), −4,+del (5)(p11),+del(6)(q21), der(7)t(7;13)(q11;q11),+der(7)t(7;?)q11;? ),i(8)(q10), −9, −10,add(11)(p14),+del(11) (q14), −13, −13, −14,der (14) 4 65~80<3n>,XX,-X,+del(1)(p34.1),del(3)(p21),+del(3)(p21),del(4)(p14),+del(4)(p14),+6, +del(7)(q32)x2, −8,+9 [8],9 [7], −10, −11,hsr(11)(q13)x2,der(13)t(8;13)(q11;p11)x2, +der (13) 10 103~129<5N>,XX,-X,-X,-X,+1,+2,del(3)(p13), −4, −5,i(5)(p10)x2,+7,+del(7)(q22)x2, −8, −8, i(8)(q10)x2, −9, −9,i(9)(q10),+10,+del(10)(q23)x2,+11,+der(11)(pter→q13::hsr::q14→q25:: hsr::? )x2, −13,+14,+der (14)t(11;14)(q11;p11)x2, −15, −16, −16, −16,-17,del(17)(p11)x2, −18, +20,+20,+20, −21, −22, −22, −22, +2mar1,+2mar2,1~3dmin[cs11]/58~63,X,-X,-X, −2, −3, −4,i(5)(p10)x2, −6,+del(7)(q22), −8, −8,i(8)(q10), −9,i(9)(q10),+10,+del(10)(q23),der(11)(pter→q13::hsr:: q14→q25::hsr::?…”

11q13 amplification status and human papillomavirus in relation to p16 expression defines two distinct etiologies of head and neck tumours

“…The oropharynx included sites involving the base of tongue, soft palate, tonsil and overlapping lesions of the oral cavity and pharynx. Analyses of TP53 mutation status (Law et al, 1995) and (Gollin et al, unpublished data), p16 immunohistochemistry (unpublished data) and 11q13 amp (Shuster et al, 2000;Lese et al, 1995) were performed in earlier unpublished studies unless otherwise noted. Briefly, TP53 mutation status was determined by automated sequencing of exons 5 -8, p16 immunohistochemistry was performed on paraffin sections of formaldehydefixed tissue using a monoclonal antibody to full length human p16 protein (Vector Labs, Burlingame, CA, USA).…”

“…Common genetic alterations in HNSCC involve TP53, CDKN2A/p16 and chromosomal band 11q13. Amplification of 11q13 is among the most common sites of gene amplification, observed in a number of cancers (Schraml et al, 1999), and in approximately 45% of HNSCC (Lese et al, 1995;Schuuring, 1995;Gollin, 2001). A number of putative oncogenes map to this region; among them, CCND1 (cyclin D1) is thought to play a role in tumorigenesis.…”