Tissue Fixation with a Formic Acid-Deprived Formalin Better Preserves DNA Integrity over Time.

INTRODUCTION: Optimization of pre-analytic procedures and tissue processing is a basic requirement for reliable and reproducible data to be obtained. Tissue fixation in formalin represents the extensively favored method for surgical tissue specimen processing in diagnostic pathology; however, formalin fixation exerts a blasting effect on DNA and RNA. METHODS: A formic acid-deprived formaldehyde solution was prepared by removing acids with an ion-exchange basic resin and the concentrated, acid-deprived formaldehyde (ADF) solution was employed to prepare a 4% ADF solution in 0.1 M phosphate buffer, pH 7.2-7.4. Human (n = 27) and mouse (n = 20) tissues were fixed in parallel and similar conditions in either ADF or neutral buffered formalin (NBF). DNAs and RNAs were extracted, and fragmentation analyses were performed. RESULTS: Besides no significant differences in terms of extraction yield and absorbance ratio, ADF fixation reduced DNA fragmentation, i.e., the largest fragments (>5,000 bp) were significantly more prevalent in the DNAs purified from ADF-fixed tissues (p < 0.001 in both cohorts). Moreover, we observed that DNA preservation is more stable in ADF-fixed tissue compared to NBF-fixed tissues. CONCLUSION: Although DNA fragmentation in FFPE tissues is a multifactor process, we showed that the removal of formic acid is responsible for a significant improvement in DNA preservation.

Long Covid: where we stand and challenges ahead.

Post-acute sequelae of SARS-CoV-2 (PASC), also known as Post-Covid Syndrome, and colloquially as Long Covid, has been defined as a constellation of signs and symptoms which persist for weeks or months after the initial SARS-CoV-2 infection. PASC affects a wide range of diverse organs and systems, with manifestations involving lungs, brain, the cardiovascular system and other organs such as kidney and the neuromuscular system. The pathogenesis of PASC is complex and multifactorial. Evidence suggests that seeding and persistence of SARS-CoV-2 in different organs, reactivation, and response to unrelated viruses such as EBV, autoimmunity, and uncontrolled inflammation are major drivers of PASC. The relative importance of pathogenetic pathways may differ in different tissue and organ contexts. Evidence suggests that vaccination, in addition to protecting against disease, reduces PASC after breakthrough infection although its actual impact remains to be defined. PASC represents a formidable challenge for health care systems and dissecting pathogenetic mechanisms may pave the way to targeted preventive and therapeutic approaches.

Micropapillary ductal carcinoma in situ of the breast: an inter-institutional study.

The clinical significance of micropapillary growth pattern in ductal carcinoma in situ is controversial and the impact of nuclear grading in terms of recurrence of this lesion is yet to be clarified. Our aim was to evaluate, on a series of micropapillary in situ carcinomas, the histological features correlated with recurrence and whether the micropapillary subtype had a different behavior from other non-micropapillary ductal carcinoma in situ. We collected 55 cases of micropapillary in situ carcinomas from four institutions. All cases were reviewed for nuclear grade, extent, necrosis, microinvasion and tested for estrogen and progesterone receptors, Ki67, HER2, EGFR and p53 expression. Clinical data, type of surgery and follow up were obtained for all patients. Our results showed that the nuclear grade is crucial in determining the biology of micropapillary carcinoma in situ, so that the high nuclear grade micropapillary ductal carcinoma in situ more frequently overexpressed HER2, showed higher proliferation index, displayed necrosis and microinvasion and was more extensive than low/intermediate nuclear grade. Logistic regression analysis confirmed the high nuclear grade (Odds ratio: 6.86; CI: 1.40-33.57) as the only parameter associated with elevated risk of local recurrence after breast-conserving surgery. However, the recurrence rate of 19 micropapillary carcinoma in situ, which were part of a cohort of 338 consecutive ductal carcinoma in situ, was significantly higher (log-rank test, P-value=0.019) than that of non-micropapillary, independently of the nuclear grade. In conclusion, although nuclear grade may significantly influence the biological behavior of micropapillary ductal carcinoma in situ, micropapillary growth pattern per se represents a risk factor for local recurrence after breast-conserving surgery.

Gefitinib (ZD1839): therapy in selected patients with non-small cell lung cancer (NSCLC)?

PURPOSE: To evaluate response rate, toxicity and epidermal growth factor (EGFR) mutations and gene copy number as outcome predictive factors in Italian patients with non-small cell lung cancer (NSCLC) treated with gefitinib (Iressa) in an expanded access program (EAP). PATIENTS AND METHODS: A total of 137 patients with advanced NSCLC received gefitinib as first line treatment or after failure of chemotherapy. In 43 cases, tissue specimens were available for EGFR status evaluation: immunohistochemical (IHC) for EGFR, fluorescence in situ hybridisation (FISH) or Chromogenic in situ hybridisation (CISH)-(ISH) analysis for EGFR and HER2 gene copy number, and PCR-DNA sequencing for mutational analysis of EGFR were performed. RESULTS: In the study population, response rate (PR) was 13%; disease stabilization (DS) 26%; overall disease control rate 39%; median survival 6.3 months and time to progression 2.7 months. Toxicity was mild (G3 skin toxicity in 3% and G3 liver toxicity in 4% of patients). An EGFR-mutation was detected in 9/43 patients: Eight deletions in exon 19 and 1 missense mutation in exon 21. Increased gene copy number for EGFR and/or HER2 was detected in 17/43 patients. Response rate was significantly higher in women, non-smokers, in mutation carriers than in wild type carriers, in EGFR-trisomy/polysomy carriers and HER2-trisomy/polysomy carriers. CONCLUSIONS: In this study, response rate and toxicity to gefitinib treatment were consistent with previously reported data for whites. Female gender, absence of smoking history, EGFR-mutations, EGFR and HER2-polysomy were significantly associated with response to gefitinib therapy in NSCLC patients.

Cancer stem cells biomarkers in triple negative invasive carcinoma of the breast and associated in situ lesions.

Triple negative breast cancer (TNBC) [negative for expression of estrogen and progesterone receptors (ER, PR) and HER2÷neu protein] represent a subtype of breast cancer associated with poor prognosis and highly aggressive behavior. The characterization of stem cell in this type of carcinoma could determine the appearance of new ideas concerning origin and evolution. There is an impressive amount of data in the literature related to TNBC and a growing interest for stem cell research during the past years, but there are no data concerning the genetic characterization of stem cells in the context of cell biology of TNBC as compared with associated DCIS. We performed immunohistochemical studies for the expression and distribution of several stem cell-related antigens, focusing on the association of TNBC with DCIS and comparing the presence of stem cells in the invasive and in the in situ component. Optimization of detection, identification and characterization of tumorigenic breast cancer stem cells might permit further identification of targeted treatment.

Utility of flow cytometry immunophenotyping in fine-needle aspirate cytologic diagnosis of non-Hodgkin lymphoma: A series of 252 cases and review of the literature.

Flow cytometry (FC) immunophenotyping of fine-needle aspiration (FNA) has been reported to be useful in the diagnosis of non-Hodgkin lymphomas (NHL). The authors reviewed their 5-year experience to assess the ability that FC has in improving the diagnostic capacity of cytomorphology in the diagnosis and subclassification of NHL according to the World Health Organization's classification. FC was performed on 252 FNA specimens. These included 123 cases of NHL (89 primary and 34 recurrent lymphomas). The FC immunophenotyping included CD3, CD4, CD8, CD10, CD19, CD20, CD45, and kappa/lambda antibodies combinations in the screening panel and additional panels for B or T lineage in the presence of positivity for lymphoma after the screening. An immunologic diagnosis was obtained by FC in 90% (111/123) of cases identified as NHL. FC was able to improve the total number of NHL detected in 8 cases where cytomorphology had failed to do so. In 7% (9/123) of cases, FC failed to formulate a diagnostic hypothesis owing to the sample inadequacy; 2 cases (2%) were not identified as lymphomas by FC (1 of them considered only "suggestive" also by cytomorphology); 1 case was not identified neither by FC, nor by cytomorphology. In cases having a histologic follow-up, levels of diagnostic sensitivity and specificity of the combination cytomorphology/FC were 97% and 94%, respectively. FC applied to FNA enhanced the diagnostic potential of cytologic diagnosis and subclassification of NHL, thus avoiding the need for invasive surgical biopsies in many cases.

The oxytocin receptor antagonist atosiban inhibits cell growth via a "biased agonist" mechanism.

In human myometrial cells, the promiscuous coupling of the oxytocin receptors (OTRs) to G(q) and G(i) leads to contraction. However, the activation of OTRs coupled to different G protein pathways can also trigger opposite cellular responses, e.g. OTR coupling to G(i) inhibits, whereas its coupling to G(q) stimulates, cell proliferation. Drug analogues capable of promoting a selective receptor-G protein coupling may be of great pharmacological and clinical importance because they may target only one specific signal transduction pathway. Here, we report that atosiban, an oxytocin derivative that acts as a competitive antagonist on OTR/G(q) coupling, displays agonistic properties on OTR/G(i) coupling, as shown by specific (35)S-labeled guanosine 5'-3-O-(thio) trisphosphate ([(35)S]GTPgammaS) binding. Moreover, atosiban, by acting on a G(i)-mediated pathway(,) inhibits cell growth of HEK293 and Madin-Darby canine kidney cells stably transfected with OTRs and of DU145 prostate cancer cells expressing endogenous OTRs. Notably, atosiban leads to persistent ERK1/2 activation and p21(WAF1/CIP1) induction, the same signaling events leading to oxytocin-mediated cell growth inhibition via a G(i) pathway. Finally, atosiban exposure did not cause OTR internalization and led to only a modest decrease (20%) in the number of high affinity cell membrane OTRs, two observations consistent with the finding that atosiban did not lead to any desensitization of the oxytocin-induced activation of the G(q)-phospholipase C pathway. Taken together, these observations indicate that atosiban acts as a "biased agonist" of the human OTRs and thus belongs to the class of compounds capable of selectively discriminating only one among the multiple possible active conformations of a single G protein-coupled receptor, thereby leading to the selective activation of a unique intracellular signal cascade.