HeLa, a human cervical cancer cell line, is a non diploid epithelioid cell line isolated from cervical cancer tissue of a 31 year old black female patient in 1951.. Research has confirmed that HeLa cell lines carry HPV-18 sequences, and their genomes exhibit specific structural features such as mutations, deletions, and HapA/HapB regions, which can be clearly detected through high-throughput sequencing. HPV-18 affects the biological characteristics of HeLa cells by integrating into their chromosomes: E6 protein inhibits p53 activity, alters microRNA expression, and is also regulated by Cyclin E/CDK2 to affect DNA replication efficiency. In addition, this sequence may cross contaminate other cell lines, providing important models and evidence for HPV carcinogenesis mechanisms, cervical cancer research, and related drug development.

C-33A cells are derived from a 66 year old white patient with cervical squamous cell carcinoma. They grow in an epithelial like manner and have an unstable karyotype with passage. They exhibit abnormal expression of pRB and p53 mutations, making them insensitive to HPV. It can form a metastasis model in nude mice and is widely used in research on tumor metastasis, virus therapy, drug sensitivity, and signaling pathways. The latest research involves AMP regulation of autophagy and apoptosis, the influence of traditional Chinese medicine components, and the role of related genes, providing important models for cervical cancer research.

The HepG2 cell line originated from a 15-year-old white male liver tumor and is actually a source of hepatoblastoma. It has an epithelioid morphology and adherent growth characteristics, high proliferation, and expression of liver specific proteins such as alpha fetoprotein. It is widely used in liver cancer research, drug metabolism, and toxicity assessment, such as enhancing CYP enzyme expression through gene modification to study drug metabolism and evaluating drug-induced liver injury. However, there are limitations such as low expression of metabolic enzymes, insufficient transport proteins, structural abnormalities, and heterogeneity, which can be overcome through methods such as 3D culture, gene editing, and combining with other cell lines or in vivo models. It remains an important tool for liver cancer and liver related research.

The NCI-H1395 cell line, as an important model of human lung adenocarcinoma, has recently made multiple advances in the pathophysiology of lung cancer research. Including screening diagnostic and metastasis markers through differential expression of extracellular vesicle microRNAs, exploring the sensitivity and chemotherapy resistance of drugs such as quercetin, discovering the amplification phenomenon of ADAR1 gene, optimizing culture conditions and improving STR identification, providing multi-faceted support for lung cancer research.

The molecular mechanisms underlying the occurrence and development of non-small cell lung cancer remain a hot and difficult topic in current research. Recent studies have shown that microRNAs play an important role in the development of tumors.

NK-92 cells originate from patients with malignant non Hodgkin lymphoma and have strong cytotoxicity. At present, clinical trial results have shown limited efficacy of NK-92 cell infusion after irradiation in patients with various hematological malignancies.

The Escherichia coli expression system is a cornerstone in recombinant protein production, favored for its well-characterized metabolic pathways, rapid cell growth, high protein expression levels, and clear genetic background. Despite these advantages, a significant challenge in using this system is the propensity for protein aggregation into inclusion bodies.

Insect cell expression systems have emerged as a powerful tool for the production of recombinant proteins, particularly for applications requiring complex post-translational modifications.

Mammalian protein expression systems are now widely used in the biopharmaceutical industry for producing complex recombinant proteins. These systems use mammalian cell lines like Chinese hamster ovary (CHO) cells and human embryonic kidney (HEK) 293 cells.

Frozen section IHC is a technique that involves quickly freezing tissue samples and then using a cryostat to prepare ultrathin sections. These sections are subsequently stained with specific antibodies to target antigens. Compared with traditional paraffin - embedded section IHC, frozen section IHC has the advantages of being rapid and efficient and preserving more antigen activity. It is especially suitable for clinical situations that require rapid diagnosis and for the study of fresh tissue samples.