Cytogenetic and interphase FISH analyses of 73 basal cell and three squamous cell carcinomas: Different findings in direct preparations and short-term cell. cultures

Cytogenetic analysis performed on 73 sporadic basal cell carcinomas (BCCs) and three squamous cell carcinomas (SCCs) showed different findings in dire ct preparations (24 hours) and in short-term cell cultures. Except for loss of the Y chromosome, not one of the other clonal (+ 6, + 16, add(2)(q37), del(3)(q13), add(1)(p31), and near triploidy) or sporadic changes found in direct preparations was found in cell cultures and vice versa. Clonal triso my 6 found in two BCC direct preparations and demonstrated by interphase fl uorescence in situ hybridization in 8 other cases seems to be a nonrandom c hange in basal cell carcinoma. Immunohistochemistry showed that the cell ty pe investigated was different in the two methods of analysis used: epitheli al in direct preparations and fibroblastic in cell cultures. Thus, the resu lts obtained in direct preparations indicate the BCC or SCC epithelial kary otype, whereas the aberrations found in cell cultures indicate the presence of chromosome instability in the fibroblastic stroma. The apparent lack of correspondence between direct and indirect preparations and the presence o f clonal chromosome changes in both epithelial and stromal cells suggest tu mor cell heterogeneity of BCC, The fibroblastic stroma seems to De implicat ed in the neoplastic process, This is not evident In SCC, in which clonal c hanges are present only in direct preparations. The chromosomal distributio n of the breakpoints involved in structural changes in direct and cell cult ure preparations is random: together with those reported in the literature, the breakpoints found in BCC cultures show however, a cluster to 1p36, 3q3 3, 9q22, 14p11, 15p11, and Xp11 bands. We did not find any significant corr elations between BCC cytogenetic results and the clinical data (site, age, sex, recurrence), The incidence of cases of BCC (38%) and of SCC (100%) sho wing clonal chromosome changes agree with their benign and malignant nature , respectively. Finally, a significantly high incidence of constitutional i nv(9) and dup(9)(q11q21) was found in the group of patients with BBC. (C) E lsevier Science Inc., 2000. All rights is reserved.