Cancerization of cutaneous flap reconstruction for oral squamous cell carcinoma: report of three cases studied with the mtDNA D-loop sequence analysis

International audienceAims: tissue defects, resulting from surgical resection of oral squamous cell carcinoma (OSCC), are routinely reconstructed with skin graft. OSCC arising from the grafted skin have been described, however, it is still unclear whether primary and second tumours have a common clonal origin. By screening mitochondrial DNA D-loop region (mtDNA), we evaluated the clonal relationship between the primary OSCC and the second neoplastic features appearing in the skin graft in three patients. Methods and Results: in all the three cases, the neoplastic lesions arising in the skin graft showed a clonal relationship with the previous OSCC and, on the basis of the results obtained with the mtDNA analysis, could be considered a recurrence of the primary OSCC rather than a second primary OSCC. Conclusions: Starting from a field of genetically altered cells of the oral mucosa, the spreading of the clonal cell population to the cutaneous flap might be stimulated by cytokines produced by the grafted skin. More studies are needed to evaluate the molecular relationship between primary and second OSCC to identify patients at higher risk of developing a second tumour of the skin graft

Micromolecular methods for diagnosis and therapeutic strategy: a case study

International audienceAn intraductal carcinoma, 55 mm across, was diagnosed on a total mastectomy in a 45-year-old woman. The 2 micro-invasive areas found were too small for reliable immunostainings for estrogen, progesterone, and HER2 receptors. In the sentinel lymph-node, a subcapsular tumor embole of about 50 cancer cells was identified on the extemporaneous cryo-cut section, but not on further sections after paraffinembedding of the sample. Considering this tumor metastatic potential, we decided to assess HER2 status on the metastatic embole using pathological and molecular micro-methods. We lasermicrodissected the tumor cells, extracted their DNA, and performed droplet-digital-PCR (ddPCR) for HER2 gene copy number variation. The HER2/RNaseP allele ratio was 5.2 in the laser-microdissected tumor cells, similar to the 5.3 ratio in the HER2overexpressing breast cancer cell line BT-474. We thus optimized the adjuvant treatment of our patient and she received a trastuzumab-based adjuvant chemotherapy