Pathologically confirmed women's breast cancer: A descriptive study of Tunisian and Algerian series

BACKGROUND

Breast cancer (BC) is the most frequent malignancy among women in Tunisia and Algeria. Clinical and pathological characteristics of this cancer among these populations are not widely reported. The aim of the study was to report clinical and pathological characteristics of women's BC in a Tunisian and Algerian series.

METHODS

Pathologically confirmed 1089 BCs were gathered in the pathology departments of three Northern Tunisian hospitals: Tunis military, Charles Nicolle and Jendouba and in the pathology department of Alger Douera hospital between January 2015 and December 2020. Clinical and pathological findings of the two series: age, tumor size, histological type, grading according to Scarff-Bloom Richardson grading system, lymph node status at the time of diagnosis in axillary lymphadenectomy specimens and the immunohistochemical expression of estrogen and progesterone receptors (ER/PR), HER2 and Ki-67, were collected from the pathological reports.

RESULTS

The median age at diagnosis was 50 and 48 years in Tunisian and Algerian series, respectively (p = 0.016). The diagnosis of BC was made on surgical specimens (lumpectomy or mastectomy) in 373/491 (76%) cases of the Tunisian series and in 225/598 (37.6%) cases of the Algerian one. Median tumor size was 2.8 cm and 2.5 cm in Algerian and Tunisian series, respectively (p = 0.252). Invasive BCs not otherwise specified was observed in 440/481 (91.5%) BCs in Tunisian series and in 519/586 (88.6%) BCs in Algerian series. Axillary lymph node positive tumors were observed in 64.6% and 58.8% of Tunisian and Algerian women, respectively (p = 0.926). BCs were ER positive in 311/385 (80.8%) and 486/571 (85.1%) cases and HER2 positive in 86/283 (30.4%) and 60/385 (15.6%) cases of Tunisian and Algerian series, respectively.

CONCLUSIONS

In Tunisia and Algeria, BC has poor prognostic factors with large tumor sizes and high rates of lymph nodes involvement at diagnosis.

Diagnostic and therapeutic potential of tetanus toxin-derivatives in neurological diseases

We assessed the ex vivo reactivity of peptidic constructs of Tet1 (analog of tetanus toxin non-virulent C fragment) with sequence homology to the cysteine-active site of thioredoxin (Tet1THO) or tetralysine (Tet1PLYS) with oxidative species or axonopathic sodium cyanate (NaOCN), respectively. We then assessed their neuronal uptake in vivo in laboratory animals. The reactivity of Tet1PLYS with NaOCN (1:2.5 to 1:37.5 molar ratios) or Tet1THO with hydrogen peroxide (1:0.4 to 1:6.2 molar ratios) was assessed by mass spectrometry. Green fluorescence protein (GFP)-tagged Tet1-derivatives (3 mg/ml in artificial cerebrospinal fluid) were administered daily to rats by intramuscular injection in latissimus dorsi at lumborum at the dose of 1 μl/g of body weight, for 3 days. Motor neuron uptake was assessed after double immunolabeling for GFP and choline acetyltransferase. Mass spectrometry analysis successfully demonstrated the ex vivo reactivity of Tet1-derivatives in a concentration-dependent manner. Confocal microscopy revealed the localization of Tet1-derivatives in axons and motor neuron cell bodies. Intramuscular delivery of Tet1-derivatives appears to be a practical approach to circumvent the blood nerve barrier and selectively deliver small molecules to the nervous system, for diagnostic and/or treatment purposes.

Proximal giant neurofilamentous axonopathy in mice genetically engineered to resist calpain and caspase cleavage of α-II spectrin

We use 1,2-diacetylbenzene (1,2-DAB) to probe molecular mechanisms of proximal giant neurofilamentous axonopathy (PGNA), a pathological hallmark of amyotrophic lateral sclerosis. The spinal cord proteome of rodents displaying 1,2-DAB PGNA suggests a reduction in the abundance of α-II spectrin (Spna2), a key protein in the maintenance of axonal integrity. Protein immunoblotting indicates that this reduction is due to Spna2 degradation. We investigated the importance of such degradation in 1,2-DAB PGNA. Spna2 mutant mice lacking a calpain- and/or caspase-sensitive domain (CSD), thus hypothetically resistant to 1,2-DAB, and wild-type littermates, were treated with 1,2-DAB, 35 mg/kg/day, or saline control, for 3 weeks. 1,2-DAB induced motor weakness and PGNA, irrespective of the genotype. Spna2-calpain breakdown products were not detected in mutant mice, which displayed a normal structure of the nervous system under saline treatment. Intriguingly, treatment with 1,2-DAB reduced the abundance of the caspase-specific 120-kDa Spna2 breakdown products. Our findings indicate that degradation of Spna2 by calpain- and/or caspase is not central to the pathogenesis of 1,2-DAB axonopathy. In addition, the Spna2-CSD seems to be not required for the maintenance of the cytoskeleton integrity. Our conceptual framework offers opportunities to study the role of calpain-caspase cross talk, including that of the protease degradomics, in models of axonal degeneration.