Graft-versus-Host Disease: Role of Inflammation in the Development of Chromosomal Abnormalities of Keratinocytes

Abstract

Graft-versus-host disease (GVHD) is a major risk factor for secondary malignancy after hematopoietic stem cell transplantation. Squamous cell carcinoma (SCC) of the skin and mucous membranes are especially frequent in this setting where aneuploidy and tetraploidy are associated with aggressive disease. The current study is directed to the mechanism of neoplasia in this setting. Un-manipulated keratinocytes from areas of oral GVHD in 9 patients showed tetraploidy in 10–46% of cells when examined by florescence in situ hybridization (FISH). Keratinocytes isolated from biopsy sites of GVHD but not from normal tissue showed even greater numbers of tetraploid cells (mean 78%, range 15–85%; N=9) after culture. To mimic the inflammatory process in GVHD, allogeneic HLA- mismatched lymphocytes were mixed with normal keratinocytes. After two weeks, substantial numbers of aneuploid and tetraploid cells were evident in cultures with lymphocytes and with purified CD8 but not CD4 cells. Telomere length was substantially decreased in the lymphocyte-treated sample. No mutations were present in p53 gene, although haploinsufficiency for p53 due to loss of chromosome 17 was common in cells exposed to lymphocytes. These findings suggest that in GVHD, inflammation and repeated cell division correlates with the development of karyotypic abnormalities.

p53 Phosphorylation and TP53 Copy-Number Alterations in Chronic Graft-Versus-Host Oral Lichen Preceding Squamous Cell Carcinoma

“…The rarity of TP53 mutation herein confirms previous findings in three cases of HSCT/SCC showing the absence of TP53 mutation in exons 5-9 (Zhang et al, 2002). Our results in LPLE are also in accordance with an in vitro GVHD model, where keratinocytes showed no mutations in TP53 (Sloand et al, 2010).…”

“…TP53 copy-number alterations, whether TP53 haploinsufficiency or an increased TP53 allele copy number, were found in all LPLE-HSCT/SCC sequences, as described in different malignancies, where TP53 allele deletion can be associated with p53 accumulation without TP53 mutation (Brito-Babapulle et al, 2000;Saeki et al, 2011). These findings are in accordance with the high rate of genomic instability in oral mucosa after HSCT (Khan et al, 2010) and with the common haploinsufficiency for TP53 due to the loss of chromosome 17 in keratinocytes in an in vitro GVHD model (Sloand et al, 2010). Such genomic instability may be due to chronic nitric oxide release and/ or to replication stress.…”

DNA Damage and Repair in Epithelium after Allogeneic Hematopoietic Stem Cell Transplantation

“…In an in vitro mutation analysis system, we found that allostimulated mixed lymphocyte cultures may induce MSI in co-cultured epithelial cells [22]. These results were independently confirmed by subsequent studies from other groups, which reported that the detection of MSI [23] and chromosomal instability [24] in the epithelial tissues of patients after allo-HSCT was correlated to the presence of GvHD inflammation.…”

Graft-versus-host disease

“…34 Surveillance for secondary cutaneous tumors Conditioning regimens and prolonged immunosuppression increases the risk of secondary malignancies of the skin including SCC, basal cell carcinoma, and melanoma. 17,[35][36][37]38 The long-term risk of melanoma in pediatric patients receiving HCT may be associated with a conditioning regimen using high doses of alkylating drugs. 36 Patient age, actinic exposure, skin phototype, and previous ionizing radiation are additional risk factors in the development of nonmelanoma skin cancers after HCT 39,40 (Fig 3).…”