Characteristics of established (continuous) mammalian cell lines: which statement is INCORRECT when describing ECL behavior and properties?

Introduction / Context:
Established or continuous cell lines have undergone changes enabling indefinite proliferation. They commonly display rapid growth, reduced contact inhibition, and karyotypic abnormalities. However, absolutes (“invariably”) are risky in biology because exceptions can exist.

Given Data / Assumptions:

• ECL are typically faster-growing than primary cultures.
• Many ECL are aneuploid/heteroploid, but biology admits rare exceptions or near-diploid cases.
• Loss of spatial orientation and contact inhibition is common in transformed lines.

Concept / Approach:
Identify the statement that is overly absolute. While aneuploidy is characteristic of many continuous lines, “invariably” implies no exceptions. The safer, correct teaching is “often” or “typically” aneuploid. Therefore, the absolute claim is the incorrect statement in a rigorous sense.

Step-by-Step Solution:

Verification / Alternative check:
Cell banks report karyotypes for many lines; while heteroploidy is prevalent, not every continuous line is identically aneuploid at all times, and subclones may vary.

Why Other Options Are Wrong:

• A/C/D/E: These are broadly true descriptors of established lines (rapid growth, high density potential, reduced contact inhibition, indefinite proliferation).

Common Pitfalls:
Accepting absolute statements in biology; overlooking line-to-line heterogeneity and passage-dependent karyotypic drift.

Final Answer:
Established cell lines are invariably aneuploid (heteroploid) in every case