Using genomic scars to select immunotherapy beneficiaries in advanced non-small cell lung cancer.

In advanced non-small cell lung cancer (NSCLC), response to immunotherapy is difficult to predict from pre-treatment information. Given the toxicity of immunotherapy and its financial burden on the healthcare system, we set out to identify patients for whom treatment is effective. To this end, we used mutational signatures from DNA mutations in pre-treatment tissue. Single base substitutions, doublet base substitutions, indels, and copy number alteration signatures were analysed in [Formula: see text] patients (the discovery set). We found that tobacco smoking signature (SBS4) and thiopurine chemotherapy exposure-associated signature (SBS87) were linked to durable benefit. Combining both signatures in a machine learning model separated patients with a progression-free survival hazard ratio of 0.40[Formula: see text] on the cross-validated discovery set and 0.24[Formula: see text] on an independent external validation set ([Formula: see text]). This paper demonstrates that the fingerprints of mutagenesis, codified through mutational signatures, select advanced NSCLC patients who may benefit from immunotherapy, thus potentially reducing unnecessary patient burden.

Cytology of the vulva: feasibility and preliminary results of a new brush.

OBJECTIVE: Taking a biopsy is a standard procedure to make the correct diagnosis in patients with suspicious premalignant vulvar lesions. The use of a less invasive diagnostic tool as triage instrument to determine whether biopsy is necessary may improve patient comfort especially in patients with chronic vulvar disorders that may warrant consecutive biopsies. This study was conducted to investigate whether vulvar brush cytology is feasible and may be used to detect (pre)malignant vulvar lesions. METHODS: A pilot study was performed with patients having clinically normal vulvar skin, lichen sclerosus (LS), usual or differentiated vulvar intraepithelial neoplasia or squamous cell carcinoma. A total of 65 smears were taken with the use of a vulvar brush and biopsies were performed for histopathological analysis. RESULTS: Out of 65 smears, 17 (26%) were discarded because of poor cellularity. A total of 28 of 29 (97%) smears with a histological proven (pre)malignancy had a smear classified as 'suspicious' or 'uncertain'. Cytology classified 11 smears as 'non-suspicious', of which 10 (91%) were indeed normal skin or LS. The accuracy, based on the presence of a lesion, for (pre)malignant lesions with the use of the brush showed a sensitivity of 97% and a negative predictive value of 88%. CONCLUSION: Vulvar brush cytology is feasible and may be a first step in the development of a triage instrument to determine whether subsequent biopsy of a clinically (pre)malignant lesion is necessary.

Signet ring cell differentiation in mucinous colorectal carcinoma.

Approximately 10% of all colorectal carcinomas are mucinous carcinomas, characterized by extracellular mucin. Occasionally, mucin accumulates intracellularly in these tumours, causing signet ring cell differentiation. We hypothesized that signet ring cells arise from a separate genetic pathway. In this study the molecular background of signet ring cell differentiation was investigated by analysing genetic changes, changes in the expression of adhesion molecules, and mucin content. Furthermore, its clinical relevance was addressed. Cell lines of colorectal tumours with non-mucinous (AC), mucinous (MC), and signet ring cell phenotype (MCSRC) were used for Multiplex Ligation-dependent Probe Amplification to detect deletions and amplifications in specific oncogenes and tumour suppressor genes. Furthermore, the expression of E-cadherin, beta-catenin, ITF (intestinal trefoil factor), and MUC2 in signet ring cells was studied by immunohistochemistry, immunofluorescence, and mRNA in situ hybridization. Results were validated using a large cohort of rectal carcinomas from which clinicopathological data were available. Specific amplifications and deletions in cell lines of AC, MC, and MCSRC were detected. Bcl-2 was amplified in MCSRC and MC cell lines, but not in AC cell lines. Bcl-2 FISH analysis confirmed this in patient material. Signet ring cells had decreased expression of adhesion molecules (E-cadherin, beta-catenin) and were strongly positive for ITF and MUC2, two peptides which are normally only produced by goblet cells. RNA in situ hybridization confirmed the production of ITF. Mucinous carcinomas with signet ring cell differentiation presented at a higher T stage than adenocarcinomas and mucinous carcinomas (16% pT4 versus 3-5%, p<0.001) and were more frequently node positive (77% vs 39-44%; p<0.001). Prognosis was significantly worse. In conclusion, the presence of signet ring cells in carcinomas with mucinous differentiation correlates with increased T-stage and poor prognosis. These cells, characterized by ITF and MUC2 production, show disruption of the E-cadherin/beta-catenin complex, as well as amplification of Bcl-2.

Distinct phenotypic changes between the superficial and deep component of giant congenital melanocytic naevi: a rationale for curettage.

BACKGROUND: Giant congenital melanocytic naevi (GCMN) convey a 14-fold increased melanoma risk. In contrast, medium congenital melanocytic naevi (MCMN) are rarely associated with malignant transformation. Management of patients with GCMN is challenging and there is no consensus on the most appropriate strategy for treating these patients. OBJECTIVES: To provide a rationale for performing curettage of GCMN in the neonatal period in order to reduce the risk of malignant transformation to melanoma. METHODS: Twenty-six infants with GCMN who underwent biopsies before excisional surgery (n = 7) or curettage (n = 19) during the past 14 years (Academic Hospital, Vrije Universiteit Brussel) and 10 MCMN patients who underwent excision biopsies (Radboud University Nijmegen Medical Centre) were included in this study. Using these biopsies, we performed genetic and detailed immunohistochemical evaluations of changes that are associated with malignant transformation. Variables of interest included melanoma-associated BRAF mutations, proliferative activity, vascularity, cellular context and extracellular matrix architecture. RESULTS: GCMN and MCMN did not show oncogenic BRAF mutation and displayed similar features with respect to the amount of nonmelanocytic cells within the naevus and matrix architecture. Naevus cells in the superficial component of the GCMN, however, were more proliferative, and this component was more vascular compared with its deep component and with MCMN. In this study, none of the 19 newborn patients who underwent curettage developed a melanoma within a mean follow-up time of 7 years. CONCLUSIONS: The data presented here support the idea that curettage of GCMN in neonates has the potential for lowering the risk of developing cutaneous melanoma by not only obtaining an important numerical reduction of naevus cells but also removing the 'active' melanocytes.