Establishment and characterization of a new cell line, A99, from a primary small cell carcinoma of the pancreas.

Objectives: Small cell carcinoma (SCC) of the pancreas is a rare malignancy with a poor prognosis. We established and characterized a primary human pancreatic SCC cell line, designated A99.

Methods: Cancer tissue was obtained from the liver metastasis of an SCC of the pancreas and xenografted into nude mice. The first-pass xenograft was then used to establish a cultured cell line called A99. Cellular morphology, immunohistochemical properties, tumorigenic potential, and genetic alterations of this new line were characterized.

Results: A99 cells grew consistently in culture, formed colonies in soft agar, and grew as subcutaneous xenografts when inoculated into nude mice. A99 cells were positive for pancytokeratin, synaptophysin, chromogranin A, neuron-specific enolase, CD57 (Leu7), CD56, protein gene product 9.5, thyroid transcription factor 1, Smad4, p53, and p16, but not for CD99, PDX-1, or retinoblastoma protein. Sequencing analysis revealed homozygous point mutations of KRAS and TP53. Cytogenetic analysis revealed complex chromosomal rearrangements including marker chromosomes.

Conclusions: A99 is the first cell line reported to be derived from a primary SCC of the pancreas. The establishment of this cell line may serve as a useful model system for studying the cell biology of this rare cancer or for evaluating novel targeted agents in preclinical models.