p53 Mutations in Deep Tissues Are More Strongly Associated with Recurrence than Mutation-Positive Mucosal Margins

Abstract

Purpose: Application of ultrasensitive diagnostics has shown that small numbers of p53 mutation-positive cells may signify the presence of residual tumor in histologically normal tissues after resection of squamous cell carcinomas arising in the head and neck area. To date, most studies in this area have focused on analysis of tissues at the mucosal aspect of the resection and highlighted the importance of molecular changes in the field with respect to the risk of recurrence. Experimental Design: In the present investigation, we analyzed normal tissues from mucosal and deep surgical margins, referred to as ''molecular margins,'' for the presence of the signature p53 mutation identified for each tumor. Results:The p53 mutation status of these carcinomas did not correlate with clinical or histopathologic variables, but these mutations provided an excellent target for ultrasensitive analysis of margin status. We found that 11of 16 (68%) of cases with histologically tumor-free (including 9 without dysplasia), but with p53 mutation-positive molecular margins, developed recurrence.The probability of developing local recurrence was significantly higher for the group with p53 mutation-positive margins when compared with the group with clear margins (P = 0.048) and more strongly associated with p53 mutation-positive deep molecular margins than mutation-positive mucosal molecular margins or positivity at both sites (P = 0.009). Conclusions: This shows that although persistent mucosal fields may contribute to recurrence, clonal p53 mutations in deep tissues are an important cause of treatment failure, and molecular margins from both sites should be analyzed in future prospective series.

Prognostic value of cyclin D1 expression in tumor-free surgical margins in head and neck squamous cell carcinomas

“…Some groups, therefore, investigated alternative approaches to the detection of occult tumor cells in the surgical margins of patients with HNSCC [9,10]. These occult tumor cells may express factors associated with local recurrence and some of these factors, which are the result of genetic or epigenetic alterations, can be detected by IHC staining.…”

“…Alterations in p53 have commonly been found in HNSCCs, but its influence on prognosis remains controversial. In recent reports, p53 mutations, detected by molecular assays such as DNA sequencing, LigAmp assay, and real-time PCR, were considered a useful prognostic factor [9][10][11][12]. However, we previously reported that the IHC assay of p53 was not useful in predicting the prognoses of patients undergoing chemoradiation therapy [13].…”

The antiangiogenic agent ZD4190 prevents tumour outgrowth in a model of minimal residual carcinoma in deep tissues

“…Translational research, based on the application of molecular diagnostics to detect residual tumour after surgery for head and neck carcinoma, has highlighted the need to identify treatment modalities, other than radiotherapy, to prevent recurrence at the operative site (Huang et al, 2007). Vascular endothelial cell growth factor signalling inhibitors are attractive for the treatment of residual disease, as tumour regrowth is dependent on neovascularisation, and in this report, we show that ZD4190 can prevent outgrowth of malignant cells when the tumour burden is below a critical threshold.…”

“…This is important as the term surgical margins frequently causes confusion, as it may be wrongly assumed that the tissues examined are taken from the edge of the resected carcinoma, rather than from the normal tissues. Analysis of both mucosal and deep 'molecular margins' has revealed that the finding of p53 mutations in deep margins is more strongly associated with development of local recurrence than p53-mutation-positive mucosal margins (Huang et al, 2007). A second key observation that has emerged from all studies applying these new diagnostics (Brennan et al, 1995;Partridge et al, 2000Partridge et al, , 2005van Houten et al, 2002van Houten et al, , 2004Huang et al, 2007) is that multiple tumour-positive margins are associated with local recurrence, indicating that local spread is more widespread than envisaged earlier.…”

Morphometric evaluation of AgNORs can help in identifying incipient cellular alterations in clinically normal-appearing oral mucosa adjacent to oral squamous cell carcinoma

“…[20] Similar studies on adjacent normal mucosal alterations by evaluating p53 expression revealed high incidence of TP53 mutations in histologically tumor-free surgical margins. [21] Further, studies on molecular characteristics of tumor-free surgical margins confi rm genotypic alterations on the basis of loss of heterozygosity (LOH), [22] thus, evaluating early biological alterations in the mucosa adjacent to cancerous lesions is very essential for the pathologists to minimize recurrences. These fi ndings suggest AgNORs might be a valuable complement to classical histology in oral cancers.…”